The delighted couple welcomed Elijah Joseph Daniel Furnish-John on Friday January 11, 2013, reported Sun online.
The 8 pounds baby boy, a brother for John and Furnish's two-year-old son Zachary, was born in Los Angeles via a surrogate, reported Sun online.
"Both of us have longed to have children, but the reality that we now have two sons is almost unbelievable. The birth of our second son completes our family in a most precious and perfect way," the couple said in a joint statement.
"It is difficult to fully express how we are feeling at this time; we are just overwhelmed with happiness and excitement."
John, 65, who wed Furnish, 50, in 2005 after 12 years together, spoke last summer about their desire to extend their family.
"I think it is difficult to be an only child, and to be an only child of someone famous. I want Zachary to have a sibling," the 'Rocket Man' singer had said.
Zachary was born in December 2010.