Captain Jack Harkness (John Barrowman) first blessed our screens 15 years ago in the Doctor Who two-parter "The Empty Child"/"The Doctor Dances," waltzing into our lives admiring Rose Tyler's bottom (the use of "bottom" is your first indication this is a Steven Moffat episode, the man loves the word bottom, it's fine) and his relentless thirst only increased from there.
Jack Harkness is a bisexual/pansexual/omnisexual/super sexual superhero who came here to kick ass, kiss lips, and chew bubblegum and he's all out of bubblegum and can do those other things at the same time (we've all seen the Torchwood episode with Captain John Hart, amirite?).
He has a particular inclination toward the Doctor in all and any form, and can you blame him? But really he can find the beauty in everyone. EVERYONE. (We're not going to talk about Ianto, TOO SOON STILL.)
Spoilers for the most recent episode of Doctor Who! If you're not caught up just watch that Jack/John video again, you'll immediately forget there's more to this post.
In the latest Doctor Who, Captain Jack made his first Who appearance in a decade and seemingly without any hint of aging (he is no closer to becoming a big giant face than when we last left him) and immediately kisses Graham and very shortly thereafter presumably enters his mind palace and imagines a companion orgy. THAT'S OUR JACK. Never change.