Britney Spears High on Cocaine for 72 Hours Straight  2/26/07

Britney Spears' first husband has fuelled reports of the pop superstar's history of drug use - by confessing the pair once stayed awake for 72 hours, high on ecstasy and cocaine.

Alexander - whose January 2004 marriage to the 25-year-old was annulled 55 hours after they tied the knot in a Las Vegas, Nevada wedding chapel - revealed he saw the full extent of Spears' recreational drug use when they celebrated the New Year in 2004.

He says, "We used ecstasy at night to party and cocaine during the day to stay awake. Then we would take downers like Valium to come down and rest.

Britney stayed up three days straight over New Year. I couldn't keep up.

"She definitely had a problem with dugs when we were together - and that was three years ago."

Spears checked into the Malibu, California rehabilitation centre Promises on Wednesday night (21FEB07), after two failed attempts in the past week to seek counseling for her problems.