A paparazzi photographer hunted Heather Mills-McCartney then grabbed her to take her picture during a four-second assault, a court has heard.
Mr Kaycappa is accused of grabbing Lady McCartney's shoulder
Jay Kaycappa, 32, is alleged to have assaulted the estranged wife of Sir Paul McCartney in a subway on Brighton seafront in 2006.
Prosecutor Dale Sullivan said it was during a pause in his pictures that he hauled her shoulder round.
The freelance photographer from Fareham, Hants, denies the charge.
Mr Sullivan said: "It would be impossible to take photographs while you were grabbing this lady's shoulder and hauling her round."
Brighton Magistrates' Court was told that Mr Kaycappa ran after Lady McCartney as she cycled along Brighton seafront.
Mr Sullivan said he and another photographer had hunted her "like a pack of animals".
Photographs submitted to the court suggest Lady McCartney left the subway and chatted to friends after the alleged assault.
The prosecution said this proved she did not make up the attack.
Mr Kaycappa said: "If you'd just been assaulted surely your friends would grab hold of the perpetrator, surely you'd scream, let's have a reality check."
Lady McCartney told the court at a previous hearing that she had called a friend for help after becoming trapped between two photographers.
Mr Kaycappa also denies assaulting Lady McCartney's friend Mark Payne the next evening.
He said he put his hand up to protect his camera equipment when her male friends tried to stop him from taking pictures and actually thought he was going to be hit.
The court was told that in the past Mr Kaycappa had used 10 aliases, six different dates of birth and had 132 criminal convictions for dishonesty offences.
The case was adjourned until Wednesday 11 July.