Amy Winehouse has been arrested on suspicion of drug offences over a video apparently showing her smoking crack cocaine.
The troubled singer was being questioned at an east London police station.
Scotland Yard said a 24-year-old woman attended a police station by appointment and was arrested over the possession of drugs.
It said the arrest was in connection with a video of the star passed to police in January.
On January 22, a newspaper published pictures apparently showing the Rehab singer smoking crack cocaine.
Footage obtained by The Sun appeared to show her inhaling fumes from a crack pipe after a 19-minute drugs binge.
The star was also shown apparently snorting ecstasy and cocaine and admitting downing six Valium.
Sky entertainment correspondent Matt Smith said this was only the latest problem for the singer. "A couple of weeks ago she was taken to a police station and cautioned over an assault.
"The last few weeks have been up and down for Amy Winehouse - the highs of winning five Grammys and the lows of her drug addiction and seemingly not battling rehab."
He added: "Last week Mark Ronson told Sky that he isn't going to record with her. She was supposed to be doing the new Bond theme with him, but he says she's not in a fit state to record."
A spokesman for the singer said: "She is being questioned in a police station. We will be releasing a statement later."
A spokesman for Scotland Yard said: "Around 1pm today a 24-year-old women from the Camden area attended a London police station by arrangement and was arrested in connection with the alleged possession of a controlled drug.
"She remains in custody. This is in connection with an investigation connected to footage passed to the Metropolitan Police on January 22."

Drugs & Drug Law
Drugs & Drug Law
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