As Friends’ popularity grew and grew in the 1990s, so did its pulling power for A-list cameos.

During its 10 years on the air, an impressive list of celebs made guest appearances in Friends, some of which are very well-remembered.

Billy Crystal and Robin Williams’s irreverent appearance in Central Perk springs immediately to mind, while others are often forgotten (who else still gets a surprise every time Charlie Sheen pops up when you’re watching Friends repeats or re-streaming on Netflix?).

As the show celebrates its 25th anniversary, we’re putting your Friends knowledge to the test, and seeing how many of the show’s most famous guest spots you can still name from memory…