Bill Nighy
Sheen’s Underworld co-star Bill Nighy has also appeared in Doctor Who under similar circumstances. Nighy is known for his frequent collaboration with Richard Curtis, often appearing in his romcoms such as Love Actually and About Time. So, when Curtis wrote an episode of the sci-fi series in 2010, naturally the actor dropped by for a cameo.
In “Vincent and the Doctor,” Matt Smith’s Doctor and Amy Pond (Karen Gillan) take Vincent Van Gogh (Tony Curran) to the future to see his work in an art gallery, to prove that he’ll be appreciated by the world at large. The curator of the gallery is Nighy’s Dr. Black, a man after the Doctor’s own heart due to their mutual love of bow ties.
After his appearance in the show, the actor dropped the bombshell that he had been offered the lead role at one point in the 2000s. He turned it down, however, as he thought the part came with “too much baggage.”
Simon Pegg And Nick Frost
Simon Pegg is a veritable geek icon thanks to his roles in Star Trek, Mission: Impossible and, of course, his “Cornetto trilogy” of comedy genre movies – Shaun of the Dead, Hot Fuzz and The World’s End. It’s often forgotten, though, that he’s also ticked off two other sci-fi juggernauts in Star Wars and Doctor Who. Back in 2005, Pegg appeared in “The Long Game” as the Editor, the sinister albino assistant to a giant slug-like monster that was secretly controlling all of the Earth’s media.
Many years later, Pegg’s frequent on-screen best bud Nick Frost also appeared in the show. In 2014’s “Last Christmas,” Frost played none other than Santa Claus in an Inception-like Christmas special that saw Peter Capaldi’s Doctor trapped in a dream world set at the North Pole (hence the inclusion of St. Nick).
The end of the episode left it ambiguous whether Santa really exists in the Doctor Who universe or not, so Frost could theoretically return at some point.