Christina Aguilera’s fourth studio album is finished and “amazing”, according to US songwriter Tricky Stewart.

Stewart, the man behind Rihanna’s Umbrella and Beyonce’s Single Ladies, said to Rap-Up.com: “I really feel it’s one of her best bodies of work that I’ve heard since Stripped. I think it’s really, really amazing and I think it’s well put together.”

The album is the follow-up to the 28-year-old’s 2006 album Back to Basics and Stewart said: “It’s just great. I wouldn’t say that it’s alternative, I wouldn’t say that it’s different.

“Christina’s always been an artist that moves the bar and that’s what the great ones do. They don’t stay in the same place for too long and this album is just another move for her.”