Victoria Beckham has given birth to a baby girl, whom she and husband David have named Harper Seven.
On his Facebook page, footballer Beckham said: "I am so proud and excited to announce the birth of our daughter Harper Seven Beckham."
The girl was delivered at Cedars Sinai hospital in Los Angeles, at 7.55 local time (1555 BST), and weighed 7lb 10oz.
The Beckhams' sons Brooklyn, 11, Romeo, eight, and Cruz, five, were said to be "delighted to have a sister".
David Beckham's Facebook statement said his 37-year-old wife was "doing really well" following the birth.
Mrs Beckham, 37, has swapped pop for fashion in recent years, launching her own successful label.
Previously she was one of The Spice Girls, who dominated the music charts in the late 90s with hits such as Wannabe, Mama and 2 Become 1.
The group, who reformed for a world tour in 2007, have sold 75 million records.
She married David in 1999.
On Friday, he met the Duke and Duchess of Cambridge as they started their trip to California. The Beckhams attended the Royal Wedding in April.
He is England's most capped outfield player and a former captain, and won six Premier League titles and the Champions League with Manchester United.
He went on to win the Spanish league with Real Madrid after a £25m move from United before joining LA Galaxy. He has also spent two loan spells at Italian giants AC Milan.