On Tuesday, while the rumor mill churned out the next possible James Bond candidate — David Beckham? — the British singer Sam Smith shed some light on another Bond mystery.

Mr. Smith, 23, winner of this year’s Grammy for best new artist, announced he would be singing the next Bond theme song to accompany “Spectre,” the latest (and probably last) of the actor Daniel Craig’s appearances as the suave special agent.

“I am so excited to be a part of this iconic British legacy and join an incredible lineup of some of my biggest musical inspirations,” Mr. Smith wrote in a Facebook post on Tuesday.