Champion cyclist Sir Chris Hoy is "amazed, delighted and a little shocked" after the birth of his son Callum two months early.
The tiny Callum David Robert Hoy was born at 2pm today at 29 weeks.
Sir Chris announced the news hours later on Twitter and said that the baby and his mother Sarra are both doing well.
Six-time Olympic champion Sir Chris, who retired last year, thanked medical staff for their "incredible" help.
He tweeted: "Amazed, delighted & a little shocked to announce the birth of our beautiful baby son, Callum David Robert Hoy! Born at 29weeks, today at 2pm."
Moments later he shared a picture of tiny Callum's hand clutching his finger and added: "Although v. early days for wee Callum, he's doing well as is Sarra. Huge thanks to incredible medical staff."
The former cyclist was flooded with messages congratulating him and his family.
Fellow Olympic gold-medallist Rebecca Adlington tweeted: "congratulations to you both! Hope Sarra is going well as well as baby Callum! Xx"
Sir Chris thanked everyone for their support and said: "Wow! Thanks for the huge load of messages coming in, I'm reading as many of them as I can to Sarra and Callum."
He previously spoke of his excitement about becoming a father for the first time.
"I think maybe I'm just blindly optimistic that it's going to be great fun and dead easy. I'm just very excited," he said.
"It's a very exciting period of my life and for me and Sarra, hopefully a wonderful experience."
Since retiring, Sir Chris has taken up motorsport with plans to compete at the 24-hour Le Mans race in 2016, started his own bicycle company and is acting as an ambassador with various charities.