Steve Martin’s become a first-time dad at 67, Page Six has exclusively learned. The “It’s Complicated” star and his wife, Anne Stringfield, 41, welcomed a child in December and have been spotted nearby their LA home with the bundle of joy. “They’ve had a baby, and how they kept it a secret nobody knows,” a source said. “Steve’s very private.” The source added, “They are thrilled. They worked hard to have the baby.” The couple married in 2007 at Martin’s home in a surprise ceremony where guests, including Tom Hanks and Diane Keaton were told it was a party. Martin, meanwhile, has written of his own dad: “My father’s attitude toward my show-business accomplishments was critical. After my first appearance on ‘Saturday Night Live’ . . . he wrote a bad review of me in the newsletter of the Newport Board of Realtors where he was president.” But Martin wrote in 2008, years after his father died, “In his death, my father . . . did something he could not do in life. He brought our family together.” A rep for Martin declined to comment.