Popsugar Entertainment Nostalgia Friends Guest Stars 24 Friends Guest Stars You Might Have Forgotten About 23 September 2019 by Hedy Phillips View On One Page Photo 15 of 22 ADVERTISEMENT () Start Slideshow Share This Link Copy ← Use Arrow Keys → 15 Billy Crystal and Robin Williams as Tim and Tomas These two make a quick and funny cameo in season three as Tim and Tomas in Central Perk. Previous Next Start Slideshow NostalgiaFriendsTV