Actress Billie Piper has spoken out about motherhood and said it is her toughest role yet.

Piper, who is promoting her 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."

RTE