Penny Lancaster has given birth.

The 39-year-old model and her rocker husband Rod Stewart welcomed a 7lb 12oz baby boy named Aiden - a younger brother to their five-year-old son Alastair - at London's Portland Hospital yesterday (16.02.11), and are "thrilled" with their new arrival.

A representative said: "After the long awaited arrival of their second child, Rod and Penny and proud and thrilled to welcome Alastair's baby brother Aiden into the world.

"Born February 16, 2011, weighing 7lb 12oz, mother and baby are healthy and blissfully happy."

Model Penny - who turns 40 next month - had to undergo three rounds of in-vitro-fertilization (IVF) treatment before she became pregnant, and she admitted to crying when she found out.

She said: "I couldn't believe it. I burst into tears. I called Rod when I was still sobbing. Rod said, 'I'm in the middle of a restaurant in Russia, crying.' I kept pinching myself. Neither of us could believe it."

Penny has previously revealed they wanted to have another child because Alistair was desperate for a sibling.

She said: "Rod and I felt blessed already with Alastair but he's always talked about his friends who had sisters or brothers. He'd return from play dates with my brother's kids and say, 'It's not fair, they've got each other and I have no one.'

"Alastair really wanted a little companion and always said he wanted a baby. I'd tell him it takes three things - Mummy, Daddy and God - and that maybe God thinks we're so lucky to have him that he wants to give babies to other people who don't have children. I said we were trying and praying and putting in as much effort as possible to give him a brother or sister."