Bradley Cooper wowed a talk show audience with an air guitar routine to celebrate his 40th birthday.

The 'American Sniper' star donned a huge afro wig to show off his skills to Neil Young's 'Down by the River' on 'The Tonight Show Starring Jimmy Fallon' last night (05.01.15), after confessing he had learnt the routine as a youngster.

The actor - who celebrated his 40th birthday yesterday - impressed with his energetic mock performance of the 1969 hit.

He told host Jimmy: ''I play an air guitar. When I was a little kid I had a lot of time on my hands and I just loved ... there is one song by Neil Young. I'm not sure if everybody knows this and I'm sort of proud that I know it. It's 'Down by the River'. It's just the guitar solo from 'Down by the River'.

''I didn't memorise how to play it, just to air guitar it. It's so meaningless. I'd love to try it.''

Bradley was promoting his new Broadway show 'The Elephant Man' on the show and recently revealed he is really enjoying performing in New York and is happy to have more time on his hands.

He said: ''I'm the most fulfilled I've ever been artistically. This lifestyle of doing it, being able to show up and tell a story to 740 strangers every day and sometimes twice a day, and you have the rest of your day free. It's ideal, and in New York, it's absolute heaven.''