Cher's son Chaz Bono has signed on for a sequel to his documentary film Becoming Chaz.

The 41 year old, who was born a girl, allowed directors Fenton Bailey and Randy Barbato to film him as he underwent gender reassignment surgery in 2008.

terrified for her son ahead of the operation

The documentary features footage of Bono preparing to go under the knife to remove his breasts, while his superstar mum Cher admits to the cameras that she is "terrified" for her son ahead of the operation.

Bono joined Bailey and Barbato to unveil the finished product at the Sundance Film Festival in Utah on Sunday (23Jan11), when the filmmakers revealed a sequel is already in the works.

And Bono is more than happy to allow the cameras to keep rolling, because he wants his experience to help others who may be struggling with their own sexual identities.

He tells Eonline.com, "I wanted to do this because I wanted to help people. And I knew that... I could put a face on this issue that people justdon't understand because it's a hard one to understand. I wanted to be able to change people's hearts and minds on this".

Reports from Sundance suggest Oprah Winfrey is hoping to buy the documentary and air it on her new Own TV network.