Britney Spears is reportedly using an asthma inhaler in a bid to lose weight.
The troubled singer, who does not suffer from the respiratory illness, is allegedly puffing on the medical aid to suppress her appetite.
A source told Us Weekly magazine: "Britney doesn't have asthma. She's using the chemical epinephrine, found in asthma medications, as an appetite suppressant."
Friends are extremely concerned about her reported use of the inhalers as Australian cover girl Krissy Taylor died from using a similar weight loss method.
The 17-year-old model, who had appeared in Vogue, Cosmopolitan and Elle magazines, suffered a fatal heart attack after using an inhaler to control her appetite.
Medics warn side effects include headaches, dizziness, nausea and an irregular heartbeat.
Britney - whose figure was criticised after her performance at the MTV Video Music awards, in which she wore a sparkly bra and hotpants - has told pals she will "do anything" to lose weight.
Meanwhile, Britney's former bodyguard has claimed the 25-year-old star made him hold a curtain around her table as she took drugs in a nightclub.
Tony Barretto - who was fired by the Toxic singer in May - claims he saw the mother-of-two take illegal substances on at least two occasions.
He said: "One incident happened at her table. And she had me hold a curtain to make her area private and at one point it was getting kind of hard to continue to hold the curtain for such a long period of time, so I looked over and to get her approval to let go of the curtain, at which point I noticed what she was doing."
However, Barretto insists he never saw Britney take drugs in front of her two sons, two-year-old Sean Preston and one-year-old Jayden James.
This week, Barretto made sensational claims about Britney's wild lifestyle. He once feared she had suffered an overdose after finding her "completely
out of it" in a hotel room and alleges she took various drugs, including cocaine and cannabis, while he was working for her.