Sienna Miller admits she was 'annoyed' by her 14-year age gap with boyfriend Oli Green but they 'fell in love'

Sienna Miller has spoken candidly about her age-gap romance with boyfriend Oli Green, 27.

The actress, 42, has a 14-year age difference with the model and admitted that when they first started dating, it "annoyed her" at first.

In a new interview with Harper's Bazaar, Miller said that at first, she never expected anything serious – but now they share a daughter together.

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"I didn't expect to take it seriously and then quite quickly, I fell in love," she said.

"I wasn't like, 'I'm gonna get a younger boyfriend.' It was more, 'F--k! Why are you young? That's so annoying.'"

In an interview with Vogue, Miller also addressed the 14-year age gap between herself and 27-year-old model Green.

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"I would imagine it would be complicated for anyone to get their head around, but there's been nothing but love and joy," she explained.

"I don't think you can legislate on matters of the heart. I certainly have never been able to."

Miller, who once dated actor Jude Law, said the age-gap works both ways for the pair - as Green could think she "might want to be with someone older".

The actress previously let slip the gender of their child during a video interview with Vogue magazine.

When asked if her daughter Marlowe, 11, is excited to be a big sister, Miller cut in, accidentally sharing the news, "To have a sister? A baby sister?

"Oh, gender reveal by accident. I'm having a baby girl."

The Anatomy of a Scandal star laughed it off, and added: ''I have sailed through this pregnancy.''

Miller shares Marlowe with ex Tom Sturridge.

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