Alicia Keys loves the "thrill" of performing live as she knows she's never going to deliver a "perfect" performance.

The international songstress impressed with her live performance of Girl on Fire at US President Barack Obama's second inauguration ball.

Alicia improvised on a number of sections of the song, adding in lines such as 'Obama's on fire!' and ‘Everyone knows Michelle is his girl/Together they run the world'.

The 32-year-old star embraces singing live at every available opportunity.

"That's my style and that's what I love," she explained in an interview with British newspaper The Telegraph.

"Even when I'm singing on a record there's a lot of times when I'll fight for a bit of imperfection. I might not have quite hit the note to the perfect pitch but there was a soul in there and feeling that, to me, delivers the emotion of that moment. For me, doing a show, the excitement of singing live, and the possibility that you're not gonna be perfect – that's the thrill of it."

Alicia is now regarded as one of music's finest artists. However, the star didn't always feel so comfortable and confident in her abilities.

"When I first started getting into the business, a young woman in a music game that was mostly men, I did feel inadequate. How much could I possibly know? It was an experience that was so new and wildly different, it was frightening," she mused.

"I had a vision for myself and felt I wasn't allowed to express it, because people always want to tell you, 'Do it like this, don't do that, you should do this, you can't do that'. So I did feel like I had to control it. I had to claim my space. It was about demanding respect, saying 'Here's what I want', and pushing people as opposed to being pushed around. I found that if you acted like you knew what you were doing, people would believe you knew what you were doing."

Alicia wowed crowds at the half-time show for the NBA All-Star game in Houston, Texas on Sunday. The raven-haired star showed off her enviably toned figure in a stomach-baring crop top and leather trousers as she performed at the packed-out Toyota Center.

A host of stars sat courtside to take in the action, including Beyoncé Knowles and Jay-Z, Drake and P. Diddy.