Margot Robbie is a ''super-generous'' sister.

The 27-year-old actress - who is worth an estimated $12 million - likes to treat her younger brother Cameron, 23, though he insists he isn't out for a free ride from his famous sibling.

He told Australia's OK! magazine: ''[Margot] doesn't make me pay my way, she's super-generous, but I do my own thing too.''

But he jokingly added: ''In saying that, if she gets a really expensive bottle of wine, she'll be paying for that, for sure. Or if she takes a couple of chips off my plate. I'm charging a surcharge for those chips.''

Despite the 'I, Tonya' star's career taking her away from her native Australia a lot, Cameron insists their family have stayed very close and his sister - who is married to Tom Ackerley - still tries to visit as often as possible.

He said: ''We're a very close family, so we always try to be home for Christmas. Margot tries to get here as much as possible.

''We're a very close family, so we always try to be home for Christmas. Margot tries to get here as much as possible.''

Meanwhile, though Cameron claims he is ''poor'' and leads a frugal ''student lifestyle'', he recently insisted he'd never turn to the 'Suicide Squad' star for financial assistance.

He said: ''It's never so dire that I'm going to be like 'Hey, Margot!' ''

In March, the blonde beauty received a shock when she arrived for an interview with MTV Australia to promote 'Peter Rabbit', only to discover it was Cameron there to quiz her.

The hilarious moment was caught on camera, and saw Margot - who grew up on the Gold Coast hinterland - sit down with her co-star Elizabeth Debicki to do some promo when Cameron made his appearance.

She exclaimed: ''Oh my God! What are you doing?! What are you doing?! What is going on right now?! This is so crazy. You're an interviewer on MTV.''

But her playful brother quipped: ''Excuse me, this is a professional situation. Can you just calm down?''

Margot voices Peter Rabbit's sister Flopsy in the animated film alongside James Corden, who brings the titular character to life, and Cameron teased that there were similarities between the ''dim-witted'' rabbit and his older sister.

He said: ''It's funny, in the film I noticed a lot of real life correlations between the character Flopsy [and you]. She seems quite, you know at times airy and dim-witted. Do you think that was intentional casting? I just thought there was a nice correlation between you two.''

But Margot - who, along with Cameron, also has older brother Lachlan and sister Anya -retorted: ''It's funny that's what you took from it, I thought she was maybe insecure and unheard perhaps amongst her siblings. No? Didn't come across that way?''