Elton John married his long-term partner David Furnish yesterday, converting their civil partnership after laws allowing gay marriage in Britain came into force this year.
John announced the wedding by posting an invitation on Instagram.
"Sir Elton John and David Furnish request the pleasure of your company to celebrate their wedding on Sunday the 21st of December," read the invitation, with a rose-filled background.
John and Furnish later posted pictures from the ceremony, including the exchange of vows and the menu.
They also posted photos of a dinner table decorated with a huge floral arrangement of red roses.
"The tables look stunning! We had red roses at our Civil Partnership 9 years ago and they brought us so much luck. #ShareTheLove," John wrote in a caption.
He also posted a picture of the couple exchanging vows at their estate in Windsor.
Photos posted online by other celebrities showed that former footballer David Beckham and his wife Victoria were there with their children.
Actress Elizabeth Hurley also said on social media that she was attending.
John and Furnish's civil partnership was one of the first after they became legal in 2005.
John has often used his status in the music world to make statements on lesbian, gay, bisexual and transgender equality.
Prime Minister David Cameron pushed through changes to English laws last year, which came into effect in March, to allow same-sex couples to marry.
Chat show host Graham Norton yesterday tweeted: "Huge congratulations to Sir Elton John and David Furnish. Married at last!! Xxxx #ShareTheLove."
Brooklyn Beckham posted a photo of the wedding lunch menu on Instagram.
Wild mushroom soup and truffle cream was the starter, while beef short rib and caramelised onion pie with roasted potatoes and parsnips in horseradish butter was the main dish.
Chocolate pudding and vanilla ice cream was for dessert, with wedding cake to follow, while guests were served Laurent-Perrier champagne.
Brooklyn captioned his photo: "Amazing day with family and special friends. Congratulations Uncle Elton and Uncle David #ShareTheLove."
The teenager posted a photo of name cards which included his whole family - David, Victoria, Romeo, Cruz, Harper and himself.
Gary Barlow also took to Twitter. "What an incredible day @eltonjohn @davidfurnish #sharethelove," he wrote.
Comedian David Walliams tweeted that it was a "magnificent" day.