Singer Gwen Stefani says her six-month-old son Apollo must be a miracle because he was born after her son Kingston prayed for a sibling.

The 44-year-old was adamant she and her husband Gavin Rossdale didn't want to have any more children, but she was left stunned when she got pregnant with Apollo, after her eldest son Kingston, 8, asked god for another little sibling, reports femalefirst.co.uk.

Stefani, who also has Zuma, 6, said: "He (Kingston) has a direct link to god, basically. He asked me, 'Mum, are you gonna have a baby? I want you to have a baby.'

"I was like, 'It's over. We're not having any more. This is our family'," she added.

Imitating her son, she said Kingston would clasp his hands together, close his eyes and say out-loud: "Dear god, please let my mum have a baby. Please, god! Please let my mum have a baby!"

She added: "And four weeks later, I was pregnant!"