'When your best friend is your sister': Tamara Ecclestone shows her support for Petra Stunt in the midst of her bitter divorce battle with estranged husband James

She has been showing her support for younger sister Petra Stunt since details of her bitter divorce battle from husband James came to light.

And Tamara Ecclestone shared a defiant selfie of herself cosying up to the 28-year-old blonde, putting on a united front as they enjoyed some quality family time together.

The 33-year-old Formula One heiress can be seen posing with her arm around Petra, heads close together as they showcased their close bond.

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Sister, sister: Tamara Ecclestone shared a defiant selfie of herself cosying up to sister Petra Stunt, putting on a united front as they enjoyed some quality family time together

Sister, sister: Tamara Ecclestone shared a defiant selfie of herself cosying up to sister Petra Stunt, putting on a united front as they enjoyed some quality family time together

'When your best friend is your sister', Tamara captioned the snapshot.

The girls' fans rallied around them in this tough time, enthusing, 'So beautiful ..so lucky to have each other', and 'Sending my love to Petra hope she is ok'.

Tamara also posted a cute picture of her daughter Sophia, three, posing on a pony kitted out to look like a unicorn at what appeared to be Petra's celebratory 'divorce party' this weekend.

Fifi beamed as she posed atop the animal, which boasted a pink mane and a faux horn.

Celebrating: Tamara also posted a cute picture of her daughter Sophia, three, posing on a pony kitted out to look like a unicorn at what appeared to be Petra's celebratory 'divorce party' this weekend

Celebrating: Tamara also posted a cute picture of her daughter Sophia, three, posing on a pony kitted out to look like a unicorn at what appeared to be Petra's celebratory 'divorce party' this weekend

It was reported last week that Petra planned to celebrate the eviction of her estranged husband James by staging a 'street party', as event planners were seen delivering goods to her £100million mansion.

The daughter of billionaire Bernie was seen returning to the couple's property in west London, on Tuesday, days after her estranged husband left and moved into a hotel in London.

Famed event planners Banana Split were seen dropping off party equipment for the weekend's bash, including candy floss makers and a bouncy castle, ahead of a gathering to celebrate after Mr Stunt was kicked out of the mansion.

A pygmy goat and two alpacas are among the animals that have been ordered for Petra's party, according to a list that was taken into the home by an assistant.

Cute: Tamara and her husband Jay Rutland enjoyed a family outing at an art exhibition preview with Sophia in London last week

Cute: Tamara and her husband Jay Rutland enjoyed a family outing at an art exhibition preview with Sophia in London last week

Last week, a friend of Tamara's revealed how Petra's mother Slavica was so happy to see the back of Mr Stunt that she planned to throw a street party.

Petra is divorcing the father of her three children six years after their lavish £12million ceremony which took place in an Italian castle.

She is embroiled in a bitter battle with her estranged husband over their £5.5billion fortune.

The pair have hired some of the country’s most high profile divorce lawyers to represent them in High Court hearings, which are expected to start next month.

Their £158million mansion in Los Angeles and a Grade II-listed pile in the fashionable west London district – worth up to £100million – are expected to be just some of the assets fought over.

Bernie spoke last week for the first time about his daughter's divorce from her husband James Stunt, telling MailOnline: 'She has suffered an awful lot and I couldn't bear for her to suffer any more'.

Split: Petra is divorcing James Stunt, the father of her three children, six years after their lavish £12million ceremony which took place in an Italian castle.

Split: Petra is divorcing James Stunt, the father of her three children, six years after their lavish £12million ceremony which took place in an Italian castle.

He added: 'I don't like to see marriages broken up unnecessarily, she tolerated it for quite a long time. He has caused enough aggravation for Petra'.

Extraordinary details of their bitter marriage were laid bare during a highly charged court hearing last month.

F1 boss Bernie said: 'It wasn't a divorce hearing, it was simply for Petra to be able to go back to her house.

'The case was for the judge to tell him to leave. It is a rather super house to live in which he would like people to believe he owns but he doesn't'.

A friend of Petra’s 33-year-old sister Tamara said: ‘The marriage has been terrible for a year and tricky for two.

Slavica [Petra’s mum] is so delighted she has had the courage to split from him that I think she is going to throw a street party.

'She and Tamara have been worried sick for ages and the whole family has felt that he traded on the Ecclestone name.’

Close bond: Extraordinary details of their bitter marriage were laid bare during a highly charged court hearing last month. Petra's father Bernie and sister Tamara (pictured together in July 2011) have stood by her throughout 

Close bond: Extraordinary details of their bitter marriage were laid bare during a highly charged court hearing last month. Petra's father Bernie and sister Tamara (pictured together in July 2011) have stood by her throughout 

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