Being a mum is toughest role yet, says Billie

Billie Piper, who has been promoting her raunchy drama series 'The Secret Diary of a Call Girl', said she had no idea how tiring being a mum would be.

She recently enjoyed a break in Miami with her actor husband Laurence Fox and their three-month-old son, Winston.

“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! magazine.

Winston, who arrived after a gruelling 26-hour labour and an emergency Caesarean, has not yet begun sleeping through the night.

“He’s a restless sleeper,” said Piper. “He gives us hope, then he changes his routine.”

But speaking about the joy her first child has brought, Piper said: “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.”

She added: “The smiling, it’s amazing. And having a new best friend for life.”

Piper 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 told the magazine.

“If I do anything, I just pound away on the treadmill. I don’t find ways to enjoy it more because it’s pointless. It’s hard enough with a baby and thinking about work again – it gets too much.

The 26-year-old continued: “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 ass on TV, you don’t want it to look bad.”

Matt Smith, who was recently named as the successor to current Doctor David Tennant, received Piper’s backing. The pair have worked together previously.

Piper said: “Matt’s a lovely guy and he’s a stirring actor.

“He has the right energy and that is what the Doctor’s role is really all about, essentially.”

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.”