Billie Piper has told how motherhood is her toughest role yet.

The actress and her husband Laurence Fox welcomed son Winston three months ago, and Billie said being a mum is more tiring than she thought it would be.

“I had absolutely no idea how tiring being a mum was – or how hard mums have to work,” the former Doctor Who actress told Hello!

Billie – who’s been promoting her raunchy series The Secret Diary Of A Call Girl – added: “I’ve worked some sh***y hours in my life, but these are the toughest I’ve ever had.”

But the star also talked about the joys of motherhood: “That feeling of unconditional love… I used to think it was so cheesy when people said that before, but it’s something I finally understand.”

The 26-year-old revealed she has a laid-back approach about getting her figure back. “As far as I am concerned, exercise is the most boring thing in the world,” she said.

She went on: “The diet, the regime – it will start. It will be quite intense. It’s boring and hellish, I’m sure, but if you’ve got to bare your a** on TV, you don’t want it to look bad.”

Billie also praised actor Matt Smith, who was recently announced as the new Doctor Who, saying he’s “a lovely guy and a stirring actor”.

She added: “I don’t think the Doctor should be a woman. Forgive me, I know it’s not a feminist thing to say, but it’s like saying: ‘Let’s make James Bond a woman.’ It’s a man’s role.”

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