Penny Lancaster and Rod Stewart had a second child because their six-year-old son encouraged them to.
The 40-year-old model gave birth to Aiden, her second son with rocker husband Rod Stewart in February 2011 and Penny - who underwent in-vitro fertilization (IVF) treatment before conceiving - says it was little Alastair's insistence he wanted a younger sibling that spurred the couple on.
Speaking on UK TV show 'Lorraine', she said: "Alastair was the one that kept encouraging us to keep trying, saying 'Please mummy I want a brother', I was crossing my fingers actually that it wasn't a girl because he wanted a brother so much. He's ecstatic and the two of them have the most wonderful relationship."
Rod has six children from previous relationships including Sarah, who was raised by adoptive parents, Kimberly, Sean, Ruby, Renee, and Liam and Penny - who married the rocker in 2007 - says they are the "biggest, happiest family".
She explained: "I knew when I met Rod it wasn't a partnership with just two people, it was a family with everybody. There were times that were difficult at the beginning but with warmth and love and understanding we are now the biggest happiest family.
"Everyone's invited, the kids come and meet us on trips. Sean came out to Florida to meet us for the New Year, Renee's going to meet us in Australia on tour and then when we are home in Los Angeles, where we spend most of our time, they all come over for dinners, it's wonderful."