Wait, Matthew Perry’s Actual Dad Was In Friends?

Reese was a Young Hollywood star when she was hired for a two episode role in Friends, having appeared in Legally Blonde and Cruel Intentions. She played Jill, Rachel's spoiled little sister whose eyes stray too Ross, leading to a huge argument with Rachel. Off-screen, Reese got on well with Jennifer Aniston. So much so that they starred in last year's The Morning Show.

The show's trip to London saw cameos from Hugh Laurie, Jennifer Saunders, June Whitfield and Richard Branson. But the biggest coup was the appearance of Fergie herself. It was a major sign that the show had become a bonafide global sensation.

A Hollywood veteran, the daughter of Ingrid Bergman was one of few stars to play themselves. You may remember that Ross bumped into her at Central Park, shortly after removing her from his official list of celebrities he was allowed to sleep with. Attempting to convince her that this was a mere draft, she was confused. 'It's laminated...' Sorry Ross, better luck next time.

One of the coolest actresses of the Nineties and beyond, Winona was used to playing brooding teens and spirited, strong women before she popped up in Season Seven's The One With Rachel's Big Kiss. She played Melissa, a former sorority sister of Rachel who, it emerged, harboured a lifetime of feelings for her that started with a jug of margaritas, two pairs of coconut bikinis and a cheeky snog.

We learned a lot about soap acting from the film icon's depiction of Jessica Lockhart. A member of the cast of Days Of Our Lives, she discovers that her character is to be killed off, with her brain given to Joey's Dr Drake Ramoray. A confrontation becomes a romance, before she leaves Joey behind to pursue her rightful place in Mexican cinema. Fun fact: Susan's real life daughter Eva Amurri was also in this episode, as Jessica's on-screen daughter. Meta!

Speaking of sisters, Christina played Amy, Rachel's obliviously rude sister in two memorable episodes. Christina is known in the UK thanks to a long career in comedy shows like Married With Children and Samantha Who? But her profile in the US is enormous. The screams when she shows up in Friends way outweigh those offered for many other stars.

The star of Twins, Taxi, It's Always Sunny In Philadelphia, Matilda and LA Confidential (now that's career versatility) appeared as a stripper at Phoebe's bridal shower in a side-splitting cameo. Upset when Phoebe seemed repulsed by his moves, he was sated when she gave his career an enthusiastic send-off.

The Oscar-winning star of Erin Brokovich and Pretty Woman played Susie Ross in Season 2's The One After The Superbowl: Part Two. But you may know her better as Susie Underpants. She seduces Chandler as part of a cunning ruse for vengeance, leaving him in a toilet cubicle in nothing but her underwear. As she fled with her victim's clothes, she offered a parting shot: 'Why don't you call me in twenty years and tell me if you're still upset about this?' Airing in 1996, we wonder if Chandler's still sore.

George was starring in ER when he - along with co-star Noah Wyle - filmed a cameo in 1995. They played doctors who flirt with Monica and Rachel, unaware that the roommates have switched identities due to a minor medical insurance issue. America, eh?

Brad played Ross's old friend Will in Season 8's Thanksgiving Episode. It was a stand-out turn: Brad's comic timing was on point, and the storyline - which saw Rachel discover that Ross had been a member of the I Hate Rachel Club in high school - was a strong comic concept. It was all made funnier, of course, by the fact that Brad and Jennifer were married at the time. We don't think there's ever been a louder scream from the audience when the door of Monica's apartment opened to its surprise guest.

Who's the man? Paul, dad of Ross's student girlfriend Elizabeth, was the man. Embarking on a relationship with Rachel, Paul enjoyed mirror-based pep talks. But Rachel ended it when he got too in touch with his emotions for her liking.

Denise Richards really leaned in to her Bond Girl sex symbol status as Cassie, Ross and Monica's cousin who came to stay and quickly proved a distraction to Chandler, Ross and even Phoebe.