Photo: WENN.com

Elton John and David Furnish will have their hands full this Christmas, as the couple are said to be expecting their second child.

The pair have one son already, Zachary, and tabloid reports today suggest that the millionaire couple will expand their family before the end of the year with the help of a surrogate mum. It is believed that the same woman has acted as surrogate for both children.

"They are over the moon," says a surrogacy source to The Sun newspaper, before discussing the unknown woman with whom the pair have an arrangement. "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."

Elton has spoken previously of his fears over the homophobia Zachary will face growing up.

Elton John and David Furnish on holiday with Zachary in August 2012

The star revealed his conderns in an interview with the Radio Times in August of this year, saying having two gay, famous dads will cause his problems when he is older.

"Being the child of someone famous is a huge ball and chain around your ankles. It's going to be very difficult," he said. "At school other children will say, 'You don't have a mummy'.

"We've come a long way, but there's still homophobia and will be until a new generation of parents don't instil it in their children."

Photos: see more of Elton John than you possibly ever hoped...