John, 65, and Furnish have posed with the tot and first son Zachary, two, for a family snap and the singer says he shares a close bond with the mystery woman who acted as surrogate to both his children, reported Daily Mirror.
"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," John said.
Elijah, who was born in California, on January 11 was conceived using the same egg donor as elder brother Zachary.
"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," Furnish said.