Spears has been locked in an ongoing custody battle for her sons

Walters said that the 26-year-old's manager, Sam Lutfi, had contacted her.

Mr Lutfi told her the pop star was suffering from "mental issues which are treatable", Walters said on her show, The View.

Spears lost custody of her two sons earlier this month after refusing to hand them over to her ex-husband at a scheduled pick-up time.

Mr Lutfi had been staying with Spears constantly, "and he got in touch with us", Walters said.

'Trouble sleeping'

"He said that she has been to a psychiatrist and that she, I assume, is starting some kind of treatment."

"She has been having mood swings. She's been having trouble sleeping, and also she is in touch with her mother - and her mother has been very supportive of whatever it is that Britney is going to do," she said.

Troubled Spears filed for divorce from ex-husband Kevin Federline in November 2006.