Roger Federer is the father of twin girls after his wife Mirka gave birth yesterday.
In a statement released on his personal Web site and Facebook page, tennis' world No. 1 said the girls had been named Charlene Riva and Myla Rose.
"I have some exciting news to share with you," Federer's Facebook page said.
"Late last night, in Switzerland, Mirka and I became proud parents of twin girls.
"We named them Myla Rose and Charlene Riva and they are both healthy and along with their mother they are doing great.
"This is the best day of our lives."
It was the first children for the couple, who were married in April.
Earlier this month, Mirka sat courtside through the nerve-wracking Wimbledon final in which Federer beat American Andy Roddick 5-7, 7-6 (6), 7-6 (5), 3-6, 16-14 to clinch his 15th grand slam title, breaking the previous record held by Pete Sampras.
The 27-year-old Federer met his wife-to-be - born Miroslava Vavrinec in Slovakia - in 2000 when they were competing for Switzerland in the Sydney Olympic Games.
Mirka, 31, emigrated with her family to Switzerland as a small child, and after playing on the WTA Tour and retiring prematurely due to injury, she became one of Federer's managers.