First pictures of Sir Elton John and David Furnish's new baby Elijah

Sir Elton John and David Furnish have proudly shown off their new baby son for the first time and spoken about their 'pure joy' and 'close bond' with the surrogate who had both their children.

The couple revealed their feelings as they posed with Elijah Joseph Daniel Furnish-John and first son Zachary, two, for a family photograph in Hello magazine.

Sir Elton, 65, said: "I have learned that a parent's capacity for love is endless. "When another child is born, our depth of love just grows deeper and wider, so it was very emotional."

And in a touching tribute to the surrogate, he added: "She is a wonderful, kind and loving woman, who we love like a sister.

"We have a very close bond with her and were in constant touch throughout the pregnancy. She has given us two amazing gifts and we in turn have a duty of care to her and are fiercely protective of her anonymity."

Elijah, who was born in California, on January 11, was conceived using the same egg donor as elder brother Zachary.

David, 50, added: "Throughout our lives we have both loved and been loved, but the love of a parent for his or her child is different to anything else, as all parents will know.

"You find new depths of love, and experience pure joy."

The boys are at least half-brothers as they share the same egg donor, but it has not been revealed who the donor is or which man is Elijah's biological father.

On Zachary's birth certificate, Sir Elton is named as 'father' and David as 'mother', which has led to speculation that the pop star is the biological father. Zachary was born on Christmas Day 2010.

Congratulations to them on their growing family.

• The full interview is in this week's Hello!, out now.