John Barrowman, the actor who plays the flirtatious (or dare I say slutty - I mean that in a good way!) Captain Jack Harkness from Doctor Who and Torchwood does it again. A couple years ago at Comic Con, he and David Tennant shared a quick but very much lips-on-lips kiss for the audience. This year, not only does John, in the character of the very bisexual Captain Jack, sing happy birthday to a fan - and believe me, he CAN sing - but he grabs his fanboy's head and gives him a big smacking kiss! You can see it above, and if you want to see the David Tennant kiss, just watch below.