For seven years, viewers of the TGIF classic series Boy Meets World became quite familiar with the lives and loves of Cory Matthews, Shawn Hunter, and Topanga Lawrence.

As the series followed the core trio from middle school to high school to college, and from first kisses to first dates to marriage, it goes without saying that a whole lot of new characters came in and out of their lives over the course of their formative adolescent years.

Whether it was a one off boyfriend or girlfriend, or a family member who was never heard from again, or in some cases, a family member whose appearance kept changing, faces both familiar to older viewers and unfamiliar to younger ones played crucial roles in the lives of these characters.

As part of the incredibly popular TGIF block, Boy Meets World was a perfect landing place for TV stars of old and aspiring stars trying to break into the acting world.

With that said, here are the 15 Celebrities You Never Knew Were On Boy Meets World.

Mena Suvari

As we've already seen, it wasn't totally uncommon for actors to appear as multiple characters on Boy Meets World. Yet another actor to fall into that category is Mena Suvari.

The actress, best known for her roles in films such as American Beauty and the American Pie franchise, appeared in both season two and season three as completely unrelated characters.

In season two's "Danger Boy", Suvari appeared as Laura, a girl with whom Eric tried to arrange a date for Cory in order to get rid of his boring reputation. Similarly, in season three's "The Grass Is Always Greener", Suvari played Hillary, a party girl who was convinced that Cory was in fact charming ladies' man Shawn.

Adam Scott

For devoted Boy Meets World fans everywhere, it's clear that there's only one bully from the original series who left a lasting mark. Harley Keiner tormented Shawn and Cory for much of his time at John Adams, but in his absence, a different bully roamed the halls: Griff Hawkins.

Griff was a smoother operator than Harley, preferring to work on his own much of the time, rather than have Harley's lackeys him.

As it turns out, Griff Hawkins was played by someone who would prove to be a sitcom regular in years to come. Parks and Recreation's Adam Scott guest starred as the smooth-talking, impossibly cool Griff in three episodes, marking some of Scott's first acting work ever.

Jennifer Love Hewitt

"And Then There Was Shawn" is one of the most iconic episodes to come out of the entire series of Boy Meets World. Filled with hilarious parodies of popular horror tropes and over the top humor, the episode already stands out in more ways than one.

All of that is before the introduction of the cheekily named Jennifer Love Fefferman, or Feffy, is taken into consideration. As the episode's version of the typical horror scream girl, she serves no real other purpose besides allowing the show to have some fun meta commentary.

That meta commentary is, of course, twofold. Obviously, Jennifer Love Fefferman is a clear play on Jennifer Love Hewitt's real name, and her role as a scream queen type in the film I Know What You Did Last Summer.

Beyond that, though, her minor role as a love interest for Eric allowed the show to have fun with the fact that Hewitt and Will Friedle were dating in real life at the time.

Annette O'Toole

For much of the series, flower child turned class star Topanga Lawrence's family life is a mystery. It's implied time and again that her parents are rather hippie-like-- they are bohemian, artsy, and free.

When we finally meet her mother in season six, however, she's rather strait-laced and normal-seeming. The only thing denoting the possibility for a bohemian personality is her name, Rhiannon. However, we also meet her mother in the tough time of preparing to separate from her father, Jedediah.

The first time we meet Rhiannon Lawrence, she's played by a woman who's now beyond familiar for playing the kind-hearted, soft-spoken mother, Annette O'Toole.

O'Toole, of course, went on to play Martha Kent in the long-running series Smallville, offering a portrayal of one of the most comionate and protective mothers in television history.

Rue McClanahan

In the seventh episode of Boy Meets World, "Grandma Was A Rolling Stone", viewers are introduced to Cory, Eric, and Morgan's wheeling and dealing grandmother, Bernice Matthews.

Bernice is a free spirit who travels the country in a motor home, bringing zany gifts for her grand children and making lofty promises that she has a hard time keeping. She even claims that she once "shot a man in Reno just to watch him die," a joke that clearly goes over poor young Cory's head.

The woman who brought Bernice Matthews to life was none other than Rue McClanahan of Golden Girls fame. For seven years, McClanahan played the similarly larger than life Southern belle Blanche Devereaux on the series, earning an Emmy for her portrayal of the character. She also appeared in hit sitcoms such as Maude and Mama's Family in the 1970s and 1980s.

Brittany Murphy

For much of Boy Meets World's early years, Topanga wasn't really shown to have many friends outside of Cory and Shawn. In particular, the absence of familiar friends was noticeable, as this was long before Angela and Rachel would be introduced into the series.

However, for two season three episodes, Topanga did have a female best friend: Trini Martin, a loud-mouthed, totally quirky high school freshman who didn't exactly get along with Cory.

Although Trini wouldn't be seen again after the first half of season three, her portrayer would make quite a name for herself in the industry. Trini was played by the late Brittany Murphy, whose movie career included roles in hits such as Clueless, 8 Mile, and Sin City. She also provided voice work for the film Happy Feet and the series King of the Hill.

Murphy tragically died at the age of 32 in 2009 due to pneumonia.

Keri Russell

In one of the earliest episodes of the series, Mr. Feeny asks Eric if he would be willing to keep his niece company while she's in town. Eric, thinking that he couldn't possibly want to spend time with a Feeny, pretends to be sick to get out of it, only for Feeny's niece, Jessica, to turn out to be incredibly beautiful.

Naturally, Eric's fake illness disappears and he uses adorable little sister Morgan to win Jessica over.

Eric wasn't the only boy of the 1990s to be totally wowed by Jessica, either. Five years later, Jessica would come to be known by a whole other name: Felicity. Keri Russell appeared in the one episode of season one as Feeny's niece, then soon went on to have a wide-ranging career in signature roles such as Felicity, Waitress, and The Americans.

Willie Garson

It's more or less standard operating procedure for actors to appear as different characters in long-running franchise series such as Law & Order. However, in the case of Boy Meets World, the lovable and comedically gifted Willie Garson of Sex and the City and White Collar fame played three different characters, and a fourth character in Girl Meets World to boot.

In two episodes of season one, Garson is Leonard "Lenny" Spinelli, Alan Matthews' neurotic and harried assistant manager at the grocery store. In the season four episode "Janitor Dad", Garson appears as a man named Mervyn who is a candidate for a position at the Matthews family's new nature supplies store.

Garson then goes on to appear in season seven as the minister who presides over Cory and Topanga's wedding, and in season one of Girl Meets World, he plays Topanga's no nonsense lawyer boss.

Linda Cardellini

The name Lauren is most likely a name that brings up feelings of anger and betrayal for diehard fans of Boy Meets World, and especially for viewers who were particularly invested in the relationship between Cory and Topanga.

As a particularly flirtatious girl who Cory and the gang meet while staying at a ski lodge, Lauren was the first formidable threat posed to the steady foundation that had been built for the Cory-Topanga 'ship. Soon enough, her character's advances led to the two breaking up, even though her character wouldn't have much of a role going forward.

While Lauren is undoubtedly a character who fans would have a hard time forgetting, what you may not know is that she was played by none other than Linda Cardellini, who would go on to have prominent roles in shows such as Freaks and Geeks, Mad Men, and Bloodline, as well as a starring role as Velma Dinkley in the early 2000s Scooby Doo film franchise.

Fred Savage

Sometimes, talent really does run in the family. At least in the case of the Savage brothers, this seems to be true. Ben Savage, of course, starred as the wonderfully goofy and nerdy Cory across the entire series of Boy Meets World.

His older brother, Fred Savage, had previously starred as Kevin Arnold on the beloved 1988-1993 series The Wonder Years, in addition to a memorable starring role as the aptly named The Grandson in 1987's classic The Princess Bride.

Yet, despite the adorable nice guy roles that filled Fred Savage's early career, his appearance on Boy Meets World is one that lives on in infamy even to this day. In "Everybody Loves Stuart", Savage is a young professor who insists all his students address him by his first name, Stuart.

Because of his casual demeanor, students are highly social with him, and he takes advantage of this, inviting himself into Topanga's dorm room and harassing her. Cory even gets a shove in along the way, which lands the group in a disciplinary hearing, and forces them to realize that they're not just kids anymore.