1.Before his more notable acting roles, Dwayne "The Rock" Johnson guest-starred on That '70s Show as his father, Rocky Johnson, when Red and Eric attend a wrestling match.
2.Shortly before The Office began in 2005, Jenna Fischer appeared on That '70s Show as Stacy Wanamaker, whom Jackie sees as her idol because she's popular and married to a real estate agent.
3.After starring in Big Daddy in 1999, Cole Sprouse portrayed Bobby, a little kid who makes fun of Kelso after he gets lost at Funland.
4.Alongside Cole, Dylan Sprouse played Billy, Bobby's twin brother, who spits in Kelso's ice cream and tortures him too.
5.In her first-ever TV appearance, Amy Adams played Kat Peterson, a popular cheerleader who is secretly hooking up with Hyde.
6.Betty White guest-starred in four episodes as Bea Sigurdson, Kitty's mom and Eric's grandmother.
7.A few months after Mean Girls premiered in 2004, Lindsay Lohan guest-starred on That '70s Show as Danielle, a new client at the hair salon that Fez (Wilmer Valderrama) falls for. At the time, she was also dating Wilmer in real life.
8.While starring on 3rd Rock From the Sun and before 10 Things I Hate About You, Joseph Gordon-Levitt guest-starred on That '70s Show as Buddy Morgan, Eric's lab partner who kisses him because he thinks Eric might be gay too.
9.Following TheFresh Prince of Bel-Air, James Avery guest-starred in three episodes of That '70s Show in 2004. He portrayed Officer Kennedy, who is Kelso's training officer after he joins the police force.
10.While starring on The O.C., Rachel Bilson appeared on That '70s Show as Christy, a rich girl who sits next to Fez at a wedding.
11.Bruce Willis guest-starred in an episode as Vic, the head of security at the Playboy Club in Chicago who interviews Kelso for a job. Ashton Kutcher had married Demi Moore, Bruce's ex-wife, just a few months before this episode aired.
12.Two years after Married... With Children ended, Katey Sagal guest-starred on That '70s Show as Hyde's mom, Edna, who is the school's lunch lady. She notably runs off and leaves Hyde, which is why he moves in with the Formans.
13.Seth Green guest-starred in five episodes of That '70s Show during its run. He portrayed Mitch Miller, who briefly joins the gang and has a crush on Donna, which Eric hates. Notably, Seth has worked alongside Mila Kunis on Family Guy since 1999.
14.A year after Buffy the Vampire Slayer ended, Alyson Hannigan guest-starred on That '70s Show as Suzy Simpson, a police officer in training who has a crush on Kelso, but Fez has a crush on her.
15.Schitt's Creek star Chris Elliott appeared on That '70s Show as Mr. Bray, Eric's high school guidance counselor, who tells Eric about the teaching program in Africa.
16.Brooke Shields guest-starred in seven episodes as Pamela Burkhart, Jackie's estranged mother, who starts dating Bob, Donna's dad.
17.Mary Tyler Moore guest-starred in three episodes as Christine St. George, the star of What's Up Wisconsin, who hires Jackie to work for her.
18.Before starring on shows like Drake & Josh and Community, Yvette Nicole Brown appeared on That '70s Show as Sgt. Davis, a police officer who works at the jail where Hyde, Fez, and Randy are being held.
19.Star Trek: Strange New World actor Ethan Peck appeared in two episodes of That '70s Show as a young Kelso during flashback scenes.
20.Jessica Simpson appeared in three episodes as Annette, who is Kelso's girlfriend from California.
21.The Office star Leslie David Baker appeared on That '70s Show as a janitor working backstage at a Ted Nugent concert that Donna, Eric, Hyde, and Fez attend.
22.Luke Wilson showed up in six episodes as Casey, Kelso's older brother, who briefly dates Donna after she breaks up with Eric.
23.The Brady Bunch star Barry Williams guest-starred on That '70s Show as Jeff, Kitty and Red's new neighbor who moves in with his husband.
24.Alongside his The Brady Bunch costar, Christopher Knight appeared as Josh, Jeff's husband, who is mistaken for his brother.
25.Buffy the Vampire Slayer and Bring It On star Eliza Dushku portrayed Sarah, who is hired at the radio station where Donna works, and the two clash.
26.Billy Dee Williams, aka Lando Calrissian from Star Wars, showed up on That '70s Show as Pastor Dan, a pastor whom Eric and Donna go to for counseling before they get married.
27.Before starring on Parenthood, Erika Christensen appeared on That '70s Show as Stacey, who works at PriceMart with Red and has a crush on him.
28.Way before he starred as Dan Egan on Veep, Reid Scott played Ted, a resident adviser at the University of Wisconsin who invites Hyde, Eric, Fez, and Kelso to a dorm party.
29.Music legend Gloria Gaynor guest-starred in an episode as Mrs. Clark, a music teacher who cheers up Fez at prom by singing "I Will Survive."
30.Jim Gaffigan appeared in seven episodes as Roy Keene, who is Hyde's friend from a Big Brother mentor program he was in as a kid.
31.While starring on Sabrina the Teenage Witch, Melissa Joan Hart guest-starred on That '70s Show as Mary, a girl who goes on a blind date with Hyde but ends up going home with Fez.
32.Alongside her Sabrina costar, Lindsay Sloane appeared as Patty, a girl who goes on a blind date with Fez but ends up being interested in Hyde.
33.Before starring on Scrubs and The Middle, Neil Flynn portrayed the bouncer at a hip new club that lets Donna, Hyde, and Fez in, but not Eric.
34.Groundhog Day, Glee, and One Day at a Time star Stephen Tobolowsky appeared as Laurie's psychology professor, whom she is also sleeping with.
35.And finally, Justin Long played Andrew Davis, a friend of Fez's from his home country.