Judd Apatow was just a simple, unknown writer-producer when he wrote and directed three episodes of Freaks and Geeks (2000), a cult-classic TV series that will forever be known for ending-too-soon. After meeting such a talented cast, Apatow began vetting some of the same actors and actresses for his new creation, Undeclared (2001).

Though Undeclared seems to be a lot less popular than its Freaks and Geeks counterpart, its hilarious content and easy likability are undeniable. Similar to Freaks and Geeks, Undeclared was canceled after only one season. Here we examine eleven crossovers between the two shows, featuring guest star cameos and invaluable performances.

Samm Levine

Before a long string of acting gigs, Samm Levine starred as “geek” Neal Schweiber in the cult-classic Freaks and Geeks. Judd Apatow, the creator of Undeclared, asked Levine to return for a role as “Books,” the other college freshman that’s getting the brunt of pledge week alongside Steven (Jay Baruchel).

Samm Levine was once considered for the role of Barney Stinson on How I Met Your Mother, and played a guest role in one episode.

Martin Starr

Martin Starr plays Bill Haverchuck, the highly-allergic “geek” alongside besties Sam (John Frances Daley) and Neal (Samm Levine) in Paul Feig’s Freaks and Geeks. Starr returns in Undeclared as Steven’s friend from home Theo, who’s still in high school.

After Steven doubts Theo’s cool factor, Theo proves his old high school buddy wrong by becoming the hub of all things fun during their floor’s “around the world” themed party. Theo even snags the girl pretty-boy Lloyd (Charlie Hunnam) unsuccessfully tried to pursue. Martin Starr plays Roman in the show Party Down, which also stars Lizzy Caplan, his co-star thrice over!

Natasha Melnick

Natasha Melnick plays the freshman cheerleader Cindy Sanders, the object of main character Sam Weir’s affection. Sam (John Francis Daley) struggles to make a connection with Cindy, even after he finally wins her over. Melnick can also be seen in two episodes of Undeclared as Jenni, another love interest of Lloyd’s.

Natasha Melnick and Busy Phillipps also worked together in Life As We Know It; Melnick played the role of elusive bad-girl Sabrina, the love interest of main character Dino (Sean Faris).

Lizzy Caplan

Lizzy Caplan plays Sara in a four-episode arc on Freaks and Geeks, the disco dancer enthralled with Nick Andopolis (Jason Segel). Sara and Nick begin dating in the episode “Discos and Dragons,” despite Nick still not being over ex-girlfriend Lindsay Weir (Linda Cardellini).

Lizzy Caplan also plays a cameo in Undeclared as the “Beautiful Girl” momentarily featured in the pilot episode. Caplan is best known for her role as Virginia Johnson in Masters of Sex; she’s also featured in Cloverfield (2008), and Mean Girls (2004).

Seth Rogen

Seth Rogen plays a main cast member in both Undeclared and Freaks and Geeks! His very first role was Ken Miller, the “freak” in Freaks and Geeks that’s best friends with Nick (Jason Segel) and Daniel (James Franco), who Rogen would continue to work with throughout his career. After playing a role in Donnie Darko (2001), Seth Rogen returned to the silver-screen to star in Undeclared as Ron Garner, the protagonist’s new dormmate.

Rogen’s career has since taken off, landing him the lead part in huge movies such as Pineapple Express (2008) and Neighbors (2014).

Jason Segel

Jason Segel first won the hearts of his fans by playing burnout drummer Nick Andopolis on Freaks and Geeks and returned for an even better role in Undeclared as Eric, the possessive on-again-off-again boyfriend of college freshman Lizzy (Carla Gallo), who secretly devirginized Steven in the pilot episode.

Steven’s continuous fear of Eric throughout Undeclared never ceases to be hilarious, and Segel’s eerie portrayal hits home with every watch.

Busy Phillipps

Busy Phillipps got her first big break as one of the main cast members of Freaks and Geeks, playing Daniel’s (James Franco) girlfriend, Kim Kelly. Phillipps later went on to play appropriately-named Kelly in Undeclared, as Seth Rogen’s character’s girlfriend who appears in two episodes.

Busy Phillipps also played a role in Life As We Know It (2004), a short-lived TV show made by Freaks and Geeks producers Gabe Sachs and Jeff Judah. Busy Phillipps currently stars in her own late-night talk show, Busy Tonight (2018-),

Sarah Hagan

Sarah Hagan is known for her role as the straight-laced Mathlete Millie Kentner on Freaks and Geeks, but can also be seen in Undeclared as Jordana, another college freshmen hanging around the dorms.

After Jordana seems interested in Steven (Jay Baruchel), he ruins things by chasing after unavailable Lizzy (Carla Gallo). Hagan also plays a role in Mike White’s Orange County (2002).

Allen Covert

Allen Covert, known for his famous role in Grandma’s Boy (2006) and smaller parts in films like Little Nicky (2000) and The Wedding Singer (1998), is featured in both Undeclared and Freaks and Geeks.

He ironically plays Adam Sandler’s assistant in Undeclared, since the two work alongside each other so frequently and Covert has often been compared as a sidekick of sorts to the famous comedian. Covert has a small cameo in the classic non-alcoholic keg episode of Freaks and Geeks called “Beers and Weirs,” playing the “Greasy Clerk.”

Michael Beardsley

Michael Beardsley played school bully Humphries throughout the series Freaks and Geeks, featured in fourteen of the eighteen episodes filmed. Beardsley was also featured in Undeclared as “Dormie With Chip,” a very small role as one of their background dormmates.

Though he’s mainly utilized as a side character or background role, Michael Beardsley boasts over 50 acting credits.

BONUS: Alexandra Breckenridge

Alexandra Breckenridge got her start at a young age playing the small role of Shelley Weaver in Freaks and Geeks. She later went on to be featured in two episodes of Undeclared, playing Celeste, the interested single lady Eugene (Kyle Gass) brings around his depressed friend Eric (Jason Segel) to cheer him up. Breckenridge is also featured in the pilot episode of Undeclared as the “Prim and Proper Girl.”

Alexandra currently stars as Sophie in the NBC breakout hit This Is Us.