Sir Elton John said he was "overwhelmed with happiness and joy" after his wish to become a father came true.
He and his civil partner David Furnish fulfilled their dreams of having a child when their son Zachary Jackson Levon Furnish-John was born via a surrogate on Christmas Day.
Several celebrity figures congratulated the singer, with actress Elizabeth Hurley among the first to offer her best wishes.
She wrote on Twitter: "Massive congratulations to David and Elton on having their beautiful son. Can't wait for my first cuddle."
Lord Sugar expressed disbelief at the news, tweeting on the microblogging site: "Am I hearing things right on Sky News Elton John becomes a surrogate father."
He added about an hour later: "Oh well congratulations to him."
A spokesman for the singer said the proud fathers were still in California, where baby Zachary was born.
The infant, who weighed 7lb 15oz, is Sir Elton's first child with Furnish. The couple's civil partnership was formalised in 2005.
In a joint statement, the couple said that "Zachary is healthy and doing well" and declared themselves "overwhelmed with happiness and joy at this very special moment".
The identity of their son's surrogate mother is being protected and it has also not been announced who the biological father is.
Levon is the title of a track on Sir Elton's 1971 album Madman Across The Water.
The rock legend had spoken previously of his desire to become a father, announcing last autumn that he wanted to adopt a 14-month-old boy from an orphanage in Ukraine.
He revealed that the couple had always talked about adoption but that it was Mr Furnish who wanted to do it and he who had objected as he is in his 60s.
It was the death of his long-term keyboardist, Guy Babylon, that helped to change his mind in the end. Mr Babylon, who died of a heart attack aged 52 last year, had two children whom the singer described as "wonderful".
He said at the time: "What better opportunity to replace someone I lost than to replace him with someone I can give a future to?"
But his plans to adopt were reportedly thwarted by Ukrainian laws. In becoming surrogate fathers, Sir Elton and Mr Furnish are following in the footsteps of millionaires Barrie and Tony Drewitt-Barlow, who became Britain's first gay surrogate parents in 1999.
The Essex couple have five surrogate children and made history when both were named on the infants' birth certificates.
Like Sir Elton's son Zachary, the Drewitt-Barlows' first babies – twins Aspen and Saffron – were born to a surrogate mother in California.
While surrogacy has increasingly become an option for gay couples in the UK over the past decade or so, it is tightly regulated under British law and couples often consider travelling abroad, where the rules are less strict.
California is recognised as being generally accepting of surrogacy agreements, including those that involve gay and lesbian parents.
Stonewall's Guide for Gay Dads reminds would-be homosexual parents in the UK that under the 2008 Human Fertilisation and Embryology Act, the birth mother of a child born through a surrogacy arrangement is always considered the legal parent until this is changed by the courts.
The 63-year-old vocalist and pianist, who announced in the autumn that his days of writing hit songs were over, is not the first celebrity to opt for surrogate parenthood.
Sex And The City star Sarah Jessica Parker's twin daughters, Tabitha and Marion, were born via a surrogate last year.
In July, mystery surrounded the identity of the mother of footballer Cristiano Ronaldo's baby, with Portuguese Press speculating he had arranged a surrogate.
The former Manchester United winger set tongues wagging when he said he had "exclusive guardianship" of the child. But the Real Madrid star insisted that the identify of the mother would be kept confidential.
Couple who stayed together
Sir Elton John and David Furnish are a rare thing for a celebrity couple: they have been together for almost two decades and still appear to enjoy a solid union.
The pair first met in 1993 when a mutual friend invited Canadian film producer Mr Furnish to dinner with the rock legend.
Busy schedules forced the men to spend long periods apart, but on December 21, 2005, they tied the knot in a civil partnership ceremony at the Windsor Guildhall.
A galaxy of stars joined the celebrations, including Victoria Beckham, Helena Bonham Carter and Sir Michael Caine.
The guest list was not surprising for a man who has lived in the limelight for some four decades.