Margot Robbie left stunned as brother interviews her at press junket

Margot Robbie was left stunned when her brother Cameron slipped into the interviewer's chair at a recent Peter Rabbit press junket.

The 27-year-old actress was doing interviews for the new movie in her native Australia when her younger sibling entered the room to chat to her for MTV Australia.

Clearly unaware of Cameron's involvement with the network, Margot, who had been chatting to co-star Elizabeth Debicki before the interview began, suddenly spotted him and exclaimed: "Oh my God! What are you doing?! What are you doing?! What is going on right now?!"

Elizabeth, who appeared to have been warned about what was about to happen, looked on in delight as Margot told her: "This is my brother!" to which she replied, "I know".

Cameron attempted to keep the interview on track as he told his sister: "Excuse me, can you calm down? This a professional situation right now."

But Margot failed to control her shock and surprise at the situation, exclaiming to Cameron: "This is crazy! You're an interviewer on MTV!"

Undeterred, Cameron began with a question about the amount of pranks between the rabbits in the film, to which Margot replied: "I feel like you've got ammunition if we're on the subject of pranks and I'm scared!", giggling that she was trying to "sink out of frame" to avoid answering.

Cameron then got in another jab at his sister, when he noted the "real-life correlations" between her "dim-witted" character Flopsy and Margot in real life, asking her: "Was that an intentional casting choice?"

Margot's 23-year-old sibling has something of a history of mocking her. When she lost out on the Best Actress Oscar at this year's ceremony to Frances McDormand, Cameron wrote in an Instagram story: "Not good enough are ya #imstillmumsfavouriteiguess."

He later added: "Just kidding. I'm literally crying right here. Not a dry eye in the house."