They do their thing, as always! Mark, Izzie and Callie tend to a patient played by guest star Ben Vereen in an early Season Four episode of "Grey's Anatomy."

Derek and Mark used to be best friends. Slowly they've been building that back up. Can it be back to the old days again?

Dr. Erica Hahn (Brooke Smith) sizes up her sexy surgeon counterparts Derek Shepherd (Patrick Dempsey) and Mark Sloan (Eric Dane). Gotta love these three together!

Erica Hahn puts Mark Sloan in his place awfully quickly at Joe's when he tries to act upon his "thing" for her.

Lexie Grey might be onto something with this new look. But seriously folks - that's a lot of blood Nick lost. The doctors tried in vain to save him but it was a lost cause at the end.

Always a fan favorite, Mark Sloan poses for the camera.

In this photo from "Piece of My Heart," Dr. Derek Shepherd (Patrick Dempsey) gets clowned on my Dr. Mark Sloan (Eric Dane) for the awkwardness of this elevator ride.

In this photo from "Piece of My Heart," Dr. Mark Sloan (Eric Dane) enjoys a smile at the expense of his friend Derek Shepherd, who's surrounded by all sorts of women he has complicated histories with.

Callie Torres and Mark Sloan made some love in the on-call room. But surprisingly, Mark later gave her the cold shoulder.

Maybe, and not quite the way you think! Callie Torres, Erica Hahn and Mark Sloan have a conversation in "The Becoming."

In a still shot from "Losing My Mind," from the fourth season of Grey's Anatomy, Mark and Izzie have a serious conversation at Seattle Grace.

In what appears to be his final act, Nathan convinces Peter to turn on Adam. After all, he's not a nice guy.