Beyoncé has responded to rumours that her daughter Blue Ivy was born via a surrogate.

She announced her pregnancy at the MTV Video Music Awards in August 2011, and it was subsequently alleged that she wore a prosthetic baby bump and was faking the pregnancy.

However, Beyoncé has now addressed the reports in an upcoming HBO documentary about her called Life Is But A Dream.

"A stupid rumour," People quotes her. "The most ridiculous rumour I've ever had about me. To think that I would be that vain . . ."

Beyonce gave birth to Blue Ivy in January 2012 and admitted she was "scared to death" of labour but described giving birth as "the most powerful thing you can ever do in your life".

"[It was] the most beautiful experience of my life," she added. "It was amazing . . . I felt like God was giving me a chance to assist in a miracle... You're playing a part in a much bigger show."