Pop star Lily Allen was reportedly questioned by police on Thursday after a visitor to her London home was allegedly involved in a street fight.

The unnamed man left the Smile singer's north London residence followed by his unleashed Labrador, which quickly became aggressive toward a passerby's pet dog.

According to reports, the animal owners began to argue, and were seen swearing and shouting at each other in the street.

Local police were called as the angry exchange escalated, ending with Allen's pal being arrested after aiming a punch at the stranger.

The singer was seen at the door, wearing a dressing gown, after the incident had occurred. She was later questioned by police.

A source tells Wenn, "The man leaving Lily's house seemed intoxicated. His dog wasn't on a lead and went for another man's dog.

"The two men got really angry with each other, a woman became involved and called the police."

A police spokesperson was unavailable as Wenn went to press.