Britney Spears' ex husband Kevin Federline says that the singer "completely blind-sided" him when she filed for divorce in 2006.

The rapper - who has two children with the pop princess - claims that it was all Britney where their divorce was concerned.

Kevin told People, "I didn't give her an ultimatum, but I was trying to work stuff out with her, and she didn't even talk to me or anything and went behind my back and filed for divorce.

"I was completely blind-sided."

Kevin also cites his former wife's breakdown earlier this year as a low point for both Britney and himself.

"You want to talk about one of my lowest points of depression, that was probably one of them," he says.

"I was very, very worried for her 'cause I care about her. That's the mother of my children."

 See Britney on the road to recovery below