Roger Federer's wife Mirka has given birth to twin girls, the world number one announced on his website on Friday.
The 15-times grand slam winner said Charlene Riva and Myla Rose had been born on Thursday in Switzerland.
"This is the greatest day of our lives," Federer said on the website (www.rogerfederer.com).
"Mirka, Myla and Charlene are all healthy and doing very well."
The couple were married in a small ceremony in Basel (Switzerland) in April this year.
Earlier this month Federer won his 15th grand slam title defeating Andy Roddick in the four hours and 16 minute Wimbledon final.
The win helped him break American Pete Sampras's record of 14 grand slam titles as well as reclaim the world number one spot from rival Rafael Nadal.
His win at the French Open in June also made him only the sixth man -- after Fred Perry, Don Budge, Rod Laver, Roy Emerson and Andre Agassi -- to have won all four grand slam titles during their careers.