Kelly Osbourne has hit out at singer Christina Aguilera while taping a segment for her show, Fashion Police.

The 26-year-old presenter continued on from co-host Joan Rivers, who made a comment about Aguilera's choice of outfit at a recent German fashion party, and fired up her feud with the 'Beautiful' pop star, saying:

"Maybe she is just becoming the fat b**ch she was born to be. I don't know. She was a c**t to me. And she bought my house!"

"She called me fat for so many f**king years, so you know what? F**k you! You're fat too."

Watch an interview with Kelly Osbourne below: