Britney Spears began experimenting with alcohol and drugs in her early teens, her uncle has said.
According to William Spears, the Toxic star first tried alcohol as a 13-year-old before beginning to smoke marijuana the following year.
Talking to the Sun, the singer's uncle also revealed he had once taken drugs alongside his troubled niece.
"I know she did cocaine on her 18th birthday - I was there," he said. "We were at a party in an apartment and I spotted her doing a line just before I did one. We smoked pot together too.
"She has tried just about everything - cocaine, crystal meth, ecstasy," the 49-year-old welder added.
The 26-year-old starlet is currently in the midst of a lengthy legal dispute with ex-husband Kevin Federline over the custody of their two children.
This week she again failed to attend a court hearing regarding the case and her uncle fears Britney could suffer a fate similar to her grandmother Emma Jean, who committed suicide aged just 31.
He added: "Britney is in an unstable state of mind now and there is nothing anyone can do about it. She is not listening to anybody. If people think she has reached the bottom, they are very wrong. Suicide is the bottom line for Britney."
It has been reported that the singer has grown "receptive" to the idea of seeking professional help for her problems after the suspension of her visitation rights to sons Sean Preston, two, and Jayden James, one, was again upheld.
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