In the wee hours of April 23, the Grammy-winning "Rehab" singer allegedly headbutted a man outside a London pub. She voluntarily reported to a London police station on Friday to answer questions, and was arrested.
"I can confirm that a 24-year-old woman has been arrested by appointment at a central London police station and is currently in custody," a Scotland Yard spokesman told PEOPLE.
It is a policy in England to arrest a suspect before questioning her in connection to a possible crime. Winehouse has not been charged with anything.
A 38-year-old man filed a report stating he was "headbutted" by Winehouse after trying to hail her a cab at 3:20 a.m. on April 23. According to a detailed account in the British paper The Sun, she also allegedly punched another man in the face and smoked drugs on the street.
The article was accompanied by a sequence of photos, including one of Winehouse walking into a lamppost.
Winehouse – who spent time in rehab in January and won five Grammys in February – was arrested just hours after her incarcerated husband, Blake Fielder-Civil, 25, appeared in court on charges of witness tampering. Winehouse did not attend.