Sir Elton John and his partner David Furnish are reportedly expecting a sibling for their son Zachary, who will be two on Christmas Day.
The Rocket Man singer, 65, and Furnish, 50, who became civil partners in 2005, have made no secret of wanting another child.
Now The Sun reports that another baby is due next year, using the same surrogate who gave birth to Zachary.
A source close to the pair told the newspaper: "Elton and David love this lady like a sister and they feel indebted to her for life.
"Naturally she has been well rewarded. But her identity will never be revealed."
The mother is believed to have been recruited via the Centre For Surrogate Parenting in Encino, California.
She is said to be already "several months" pregnant.
The star's staff have been sworn to secrecy, but the newspaper understands a hunt is on for an extra nanny, who will be based at his mansion in Old Windsor, Berkshire.
Back in the summer, Sir Elton revealed he would like to have another child so Zachary has someone to play with.
He said: "I'd love to have more children. I want to have a brother or a sister to go to school with him so that he can have someone to play with."
In an interview for NBC's Today show, he talked about the challenges Zachary may face.
"It's going to be heartbreaking for him to grow up and realise he hasn't got a mummy. But he's so happy. I've never seen a more contented child.
"And you have never seen two more contented people as David and I."
Sir Elton, who has made no comment about the report, is currently in Australia for a sell-out tour.
It was arranged after George Michael pulled out of his dates Down Under as he continues his recovery following a life-threatening bout of pneumonia a year ago.