Friends: A-list stars you had no idea were in the show

She made the transition from precocious child star to A-lister years ago, but aged ten, Dakota Fanning played Mackenzie, a young girl who becomes Joey's confidante. She's all grown up now – and still a bit precocious.

He's starred in Dallas Buyers Club and Modern Family, but before all that, Steve Zahn played the iconic role of Canadian ice dancer Duncan, Phoebe's secret gay husband, who she married to help get a green card.

Back in 1997, Rebecca Romijn was a model who got her first-ever acting gig on Friends. She played Cheryl, Ross' beautiful girlfriend with a filthy apartment. We reckon the X-Men and Ugly Betty star can now afford a cleaner.

"Why don't you like me?" That's the big question that Alex Borstein yells as she makes her debut fronting a one-woman show that opens with the line, "Chapter One: My First Period." These days, everyone likes Alex, who voices Family Guy matriarch Lois.

Cole Sprouse played Ross' son Ben years before he caused double-trouble with his brother Dylan on The Suite Life Of Zack And Cody. Yes, they grew up and got unnervingly attractive. Consider this, guys: Ben would now be 25.

She's one of the highest-paid actresses on TV. But before Grey's Anatomy, Ellen Pompeo played Missy Goldberg, Ross and Chandler's former classmate, who used to make out with Chandler in the science lab after hours. Dr Grey would be appalled.

You will know Dan Castellaneta by his famous alter-ego Homer Simpson. But before he was rolling in "D'oh!" he appeared as a janitor at San Diego Zoo, who tells Ross what happened to his monkey, Marcel.

Proving that The Simpsons and Friends universes co-exist, here we have Hank Azaria, who's best known for playing every other character in Springfield, including Moe and Chief Wiggum. Hank played David, who breaks Phoebe's heart when he moves to Minsk.

Her Arrested Development character Anne was memorably known for being forgettable – so it's fitting that we'd forgotten about Mae Whitman's star-turn as Sarah Tuttle, an adorable Brown Bird girl who breaks her leg selling cookies. Correction: Ross breaks her leg.

Rumour has it that Jane Lynch auditioned for the role of Phoebe. Instead, she had to make do with the slightly less significant role of Ellen the estate agent. She later made her massive mark as Glee's tyrannical Sue Sylvester.