The latest single from Britney Spears, “Till the World Ends” is now available to hear online despite it being a week before the official release date.

It had been rumoured that “Til the World Ends” from the upcoming Britney album “Femme Fatale” would be making its debut on the radio next week but fans can already listen to the song on unofficial websites.

Just hours after the song was leaked Britney Tweeted: “Looks like the cat's out of the bag...”

“Femme Fatale” is due to hit the shops in the UK on March 28 and in the US on March 29 complete with her new track “Till the World Ends”, written by solo star Ke$ha.

Also on Twitter Britney said that she promised to play a final version of the single on the Ryan Seacrest radio show.

Britney Spears will be hoping that this new single will prove as popular as her last “Hold It Against Me” which was leaked in January and then went on to reach the number one spot in charts across the world including in the US, Canada and Belgium.

Meanwhile in an interview with V Magazine Britney revealed how she would be happy to be a stay at home mum to her two boys Sean Preston and Jayden James. When asked what she would do if she gave up the fame game she said: “I'd be a full time mom, which would be cool.”

She added: “I'd miss my fans and all the love the most, but I definitely would not miss having my picture taken everywhere I go. I wouldn't miss showering in arenas either. So gross!”

She also spoke of the strain the fame had on her life: “I don't think I thought about fame when I was a child. I knew I wanted to perform and I knew I wanted to be on stage but I don't think I ever thought about fame or what comes with being famous.”