Kelly Osbourne and her sister Aimee fall out

Los Angeles: Singer Kelly Osbourne refuses to talk to her sister Aimee following a huge argument and is even forcing family to hold separate Christmas celebrations.

"Aimee and Kelly haven`t spoken for months after an almighty row. They`ve always had a challenging relationship but this last row seems to have tipped them both over the edge," quoted a source as saying.

"It`s become a ­nightmare situation for the whole ­family. Sharon`s distraught about what`s happened. Neither girl will back down.

"Kelly`s been ­telling her friends that the family will have to get used to the fact that they just don`t get on. Hate is a strong word. But they really don`t like each other. Kelly doesn`t want to know and Aimee seems to have already moved on from it all," the source added.