Kelly Osbourne: 'Christina Aguilera called me fat for years'

Kelly Osbourne has criticised Christina Aguilera for her recent weight gain.

While on E!'s Fashion Police, the 26-year-old revealed that she endured abuse from the 30-year-old singer for years for her weight.

"She called me fat for years," Osbourne said.

"I was never that fat," she continued, referring to an image of Aguilera at last weekend's Michael Jackson Tribute Concert in which she donned a black unitard and fishnet tights.

Osbourne's Fashion Police co-star Joan Rivers also criticised Aguilera's figure.

"Lady Marmalade got into the peanut butter again," Rivers said.

Earlier this month, Aguilera hired a vocal coach to make her voice "even more perfect" before laying down vocals on her new tracks.

She has promised that her next album will be "heartfelt", claiming that she is hoping for a release in spring or summer 2012.