The singer was initially unsure whether she wanted to take the project, according to news posted to the official James Bond website Monday.
"There's a lot of instant spotlight and pressure when it comes to a Bond song," she was quoted as saying. "But I fell in love with the script. ... It was also a lot of fun writing to a brief, something I've never done which made it exciting."
The song was written by Adele and Paul Hepworth, who co-wrote her hit "Rolling in the Deep." It was recorded at London's famed Abbey Road Studios.
Adele posted a picture on her Twitter feed Monday of what appears to be the sheet music cover page for the song, credited to Adele - as A. Adkins - and Hepworth. Rumors have swirled for months that the Grammy-winning British singer had recorded the theme, but there had been no official announcement from producers until Monday.
The song will be available on Adele's official site on Friday, coinciding with the 50th anniversary of the release of "Dr. No," the first Bond movie. The track was available for pre-order at iTunes starting Monday.
The film, Daniel Craig's third Bond adventure, opens in Britain Oct. 26 and in the U.S. Nov. 9. The cast includes Javier Bardem, Albert Finney, Ralph Fiennes and Naomie Harris.
The theme to the last Bond film, "Quantum of Solace," was performed by Jack White and Alicia Keys.