5. Cher on Will and Grace (2000)
Jack mistakes Cher for a drag queen and calls her “Mister Sister,” claming he does a better Cher than her. When she sings “If I Could Turn Back Time” to prove she’s the real thing, Jack tries to show her how it’s really done.
4. Oprah on 30 Rock (2009)
Liz Lemon takes sleeping pills and hallucinates an encounter with Oprah on an airplane. Starting the conversation with “I’m Liz Lemon and I lost my virginity at 25,” she goes on to confess that she eats emotionally and doesn’t like her feet, and complains that she didn’t get her September issue of O magazine. Turns out “Oprah” wasn’t really Oprah at all. She was just some random middle-schooler.
3. Brad Pitt on Friends (2001)
In 2001, there was no bigger Hollywood romance than Brad Pitt and Jennifer Aniston. So when Pitt joined his then-wife on Friends' Thanksgiving show, the sweetly funny episode became a snapshot of early 2000s celebrity culture.
2. Chris Martin on Extras (2006)
Even though he’s participating in a campaign to help people in third-world countries get clean water, Chris Martin is determined to get Coldplay’s greatest hits CD in the advertisement. When the director refuses to project his album cover on a screen behind him and play “Trouble” in the background, he opens his jacket to reveal a Coldplay Greatest Hits T-shirt.
1. Scott Baio on Arrested Development (2005)
On Arrested Development, even the choices for guest appearances were part of the in-joke. The family's longtime lawyer Barry Zuckercorn was played by Henry Winkler (Happy Days' The Fonze). So when the family needed a new lawyer, Bob Loblaw (say it fast), he was, of course, played by Scott Baio.