Fashion designer Stella McCartney has given birth to her first child.
The daughter of Sir Paul gave birth to an 8lb son at the exclusive Portland hospital in London. The former Beatle is thought to have already visited his grandson.
Victoria Beckham, Zoe Ball and Patsy Kensit have all given birth there.
A spokeswoman for 33-year-old Stella and her husband, Alasdhair, said: "Stella and Alasdhair Willis are thrilled with the birth of their happy and healthy baby boy in the early hours of February 25 in London.
It's almost all in the family for Stella McCartney and her new son, Miller Alasdhair James Willis.
The fashion designer and her husband, Alasdhair Willis, turned to the McCartney family for the boy's third name, PEOPLE reports.
Stella, the son of ex-Beatle Paul McCartney, has a grandfather named James Paul McCartney, and a brother named James Louis McCartney. However, it was not clear where the name Miller originated. A representative for McCartney would not comment on the name.
Miller Alasdhair James Willis was born Feb. 25 in London. He weighed 7 lbs., 7 oz., and his mother is still recovering at an undisclosed hospital in the city. McCartney, 33, is unveiling a new line of clothing for 2006, which will show in Paris on Thursday.
"The Stella McCartney show will proceed as scheduled Thursday in Paris," her rep said, "even though Stella can't be physically present to take a bow."
McCartney is expected to be on maternity leave following her release from the hospital.