Tamara Ecclestone has had an argument with her sister Petra.

The 27-year-old socialite and her younger sibling were enjoying dinner at top Los Angeles restaurant Katsuya last Saturday night (03.09.11) when the row kicked off in front of their guests, including Petra's new husband James Stunt, and other diners.

Rumour has it Petra might be upset because Tamara is looking to move to LA - where she has just set up home in a £52 million mansion with James - and things got pretty heated at the table and Tamara eventually stormed out of the Japanese eatery.

A source told BANG Showbiz: "Tamara was stunned by Petra's behaviour and looked pretty upset by the whole incident. It was an unexpected row and took her completely by surprise."

Since the bust-up, the girls - who are the daughters of billionaire Formula 1 boss Bernie Ecclestone - are yet to properly make up and have barely spoken to each other in the last week.

The source added: "Things haven't been great, Tamara was very upset by the row they had at the restaurant. Petra has some making up to do."

Petra - who has been enjoying a honeymoon in Los Angeles after tying the knot with James in Italy in August - bought the lavish Beverly Hills property from Candy Spelling, the mother of Tori Spelling, in June.

Tamara - who is dating stockbroker Omar Khyami - joined Petra and James on their honeymoon for a short break and while she was in Los Angeles admitted she could imagine living in the sun-drenched city.

The brunette beauty - whose three-part reality TV show 'Tamara Ecclestone Billion Dollar Girl' airs in the UK from November 4 - recently said: "I would love to come over here (LA) and spend three or six months of the year here, I would love that, like, when it's raining in London. It's such nice weather, I love it . I feel like LA is kind of a world of its own, really weird, like this wonderful bubble. I feel what's nice about Los Angeles is a lot of people come here with a dream, for me it's a really inspirational place."

Tamara is currently in talks with American TV network executives about having a reality series broadcast in the US.