Robinson-Earl/Splash News Online
07/09/2008 AT 09:00 AM EDT
As the sentencing
of her husband, Blake Fielder-Civil, nears, Amy Winehouse
has been accused of lashing out at a stranger – for the third time in two weeks.
In the most recent altercation, she reportedly punched a fellow drinker at Camden's Dublin Castle pub in what was claimed was an unprovoked attack.
"She was in front of me at the bar and suddenly turned and walloped me three times across the face. It really stung," Wayne Lindsay, 29, told Britain's Daily Mirror
. "I couldn't believe it. I hadn't said a word to her or touched her."
According to the paper, the recently hospitalized
"Rehab" singer then stormed out of the North London tavern.
A source close to the singer tells PEOPLE that Winehouse merely reacted because someone grabbed her from behind – and that her security then stepped in. (The insider added that she has felt an increasing need for bodyguards in recent weeks.)
On July 7, Winehouse reportedly hit
another fan who was trying to photograph her as she returned to her home.
Both incidents follow the widely-documented episode in which the star struck out at a fan
during the Glastonbury festival.
Her rep declined to comment.