Kate Middleton's uncle, Gary Goldsmith admitted Tuesday that he punched his wife outside their home in central London after an argument sparked between the two. The 52-year-old, who has an estimated net worth of $40 million, is the younger brother of the Duchess of Cambridge's mother Carole Middleton. 

Gary was accused of assaulting Julie-Ann Goldsmith, 47, with a "left hook" during a drunken spat after they attended a party at a private members club. Gary appeared in court Tuesday and admitted to one charge of assault by beating. The businessman could face a maximum penalty of six months' imprisonment, but reports say he might get community service.

The incident that took place in October unfolded in front of a taxi driver. Prosecutor Kate Shilton told the court Julie-Ann fell down after her husband threw what was described by their taxi driver, Daniel Shepherd, as a "left hook."

"The argument took place in the back of a taxi. They both got out of the taxi and he (Shepherd) describes Mrs. Goldsmith slapping her husband to the face," Shilton told the court. "He then describes how Mr. Goldsmith punches her hard in the face using a left hook."

The taxi driver said that Julie-Ann fell to the ground and appeared to be unconscious. But after 15 seconds she woke up and staggered to her feet.

"She (Julie-Ann) then becomes upset, starts crying and uses some railings to assist her," Shilton told the court, according to the Daily Mail, adding that when the taxi driver challenged Gary over his actions, he then became aggressive towards him.

Julie-Ann was taken to hospital following the incident and was later discharged, the prosecutor told the court. 

Gary was arrested on Oct. 13 for assaulting his wife, whom he married in 2011. Gary, who is the son of a painter and decorator from West London and grandson of a miner from a pit village in Durham, has been previously married three times. The uncle of Kate, Pippa and James Middleton began his career as an IT operator after leaving school.

By the time he got married, in 1991, to his first wife, sales executive Miranda Foote, he was a 26-year-old recruitment manager, living in a $90,000 one-bedroom flat in a mansion house in Taplow, Buckinghamshire. He joined IT recruitment company Computer Futures and within six months became the director and owned shares.

"People like to think that I’m this black sheep, a bad boy. I’m not really. I’ve had my moments — I’m not totally innocent — but am I disliked by my family? No, that is simply not true. I’ve got a good heart and I care about people. We have never fallen out," Gary had told the Daily Mail in 2013 after reports surfaced that the businessman was allegedly taking cocaine in Ibiza. "The minute that story broke, Carole was on the phone apologizing to me on behalf of the family, specifically Kate, about me being suddenly thrust into the limelight."