The TV star confronted the group for filming him on their mobile phones, and was held in a headlock when he asked them leave. His mother, 58, was also pushed to the ground when she tried to intervene.
CLICK ON PHOTO FOR GALLERY
Ant, 38, had been enjoying a meal at the Old Station House in Chiswick, when the gang started making rude gestures and taking videos of him through the window.
"The youths were banging on the window, filming them and generally being a pain – and they just wouldn't let it lie," a witness told the Sun.
"Ant was completely reasonable and said, 'Leave it out lads, I'm just having a quiet meal.' But it immediately turned really nasty and one of them jumped on him and put him in a head-lock."
TV presenting duo Ant and Dec
A spokesperson for the Metropolitan Police has since confirmed that there was an incident on Spencer Road in Chiswick on Thursday 13 March. "No allegation was made and no-one suffered any notable injuries," they added.
Ant's spokesperson is yet to comment on the incident.
Sadly it is not the first time that the TV star has been the victim of an unprovoked attack. In 2011, he was watching football in the Barley Mow in Chiswick when he was assaulted by a teenager.