Elton has been named as the father of David’s baby in official documents, fuelling speculation that the boy is the singer’s biological son.

Zachary Jackson Levon Furnish-John was born by surrogate mother on Christmas Day. Despite speculation that David, 48, provided the sperm for the surrogacy because he is the younger man, it is 63-year-old Elton who has been recorded as the boy’s father at the local register office in Los Angeles. David is listed as the mother in computer documents, an official told the Daily Mail.

Initially – normally on computer documentation – a ‘father’ and ‘mother’ are listed. However, in ‘gay dad’ surrogacy cases, when the actual certificate is produced, the couple can apply to have it re-issued as Parent 1 and Parent 2.

David on December 29, 2010 told of his joy at becoming a parent. He said: "For many years we have talked about fulfilling one of our greatest wishes by becoming parents. And now this wish has been granted to us, we feel so blessed and lucky." It was suggested last night that the birth may have cost the celebrity couple up to $1million (£646,000) in fees and payments to the clinic and women involved.

Waiting nervously at the hospital with them were David’s parents Jack and Gladys, from Scarborough in Canada. David’s younger brother Peter said: "We found out about Zachary on Christmas Day, when we got a phone call with the fantastic news and that the delivery went very well. My parents were in Los Angeles, so they were there to see the little guy."

'We may have to take the tree down, Elton. Google says they need feeding from time to time.'