"Unbreakable," which is on her just-released "Unplugged (search)" album, was intended for 2003's "The Diary of Alicia Keys." But Keys decided to leave it among the outtakes.
"It's always been one of my favorite songs but it just didn't fit properly with the second album, so, I kind of put it on the shelf waiting for the perfect time," she told The Associated Press in a recent interview.
That time came when she decided to resurrect MTV's "Unplugged" concert series; it was one of the new songs she premiered during the concert, which recently aired on the network; the companion album was released Tuesday.
The up-tempo groove, which references real-life couples such as Will Smith and Jada Pinkett Smith, got an enthusiastic response from the audience. Radio response has been strong, too — it's a top 20 hit on Billboard's R&B/hip-hop chart.
"For me, as a musician, sometimes it's really a lot of fun to just debut a new song without any expectations," she said. "The response for it was so great, so it's a lot of fun to do that."
Next month, Keys starts filming her role as an assassin in "Smokin' Aces," also featuring Ben Affleck, Andy Garcia, Jeremy Piven and Ray Liotta.
Keys, 24, is thankful for her big-name co-stars.
"It doesn't all rely on my shoulders, it's a very much ensemble piece," she said of the movie, which she described as "very dark and gritty."
Though Keys is known for her soulful love ballads, she decided to pick this role for her film debut to showcase her range as an actress.
"For me personally, to go outside my character completely and become this whole new person is something that's going to be actually therapeutic in many ways," she said. "It's totally unexpected for me."