A grateful Jimmy Kimmel celebrates his son's first birthday

Entertainment-industry friends responded over the weekend to talk-show host Jimmy Kimmel and his wife Molly McNearney's grateful social-media postings Saturday, celebrating the first birthday of the couple's son Billy, who had undergone multiple lifesaving surgeries.

"God bless your family, Jimmy," tweeted Long Island native Alec Baldwin in response to Kimmel's post that read, "A yr ago today, God gave us this tough little boy. Today, we thank the nurses & doctors at @CedarsSinai & @ChildrensLA who saved his life & those who shared thoughts & prayers. We cannot stay quiet. Please wish Billy happy birthday by REGISTERING TO VOTE!"

Actor-screenwriter Justin Theroux posted four close-up photos of himself holding baby Billy, wishing him a happy birthday and calling him "[a] boy who in 365 days has done more for American national health care than we could all wish to do in our lifetimes. He doesn't even know yet how courageous he is. An honor to know him and his incredible and equally courageous parents. ❤️ Thank you @CedarsSinai & @ChildrensLA #registertovote."

Comedian Mike Birbiglia responded to a tweet by McNearney, co-head writer of ABC's late-night "Jimmy Kimmel Live!" "This photo is so damn touching," he wrote. "Happy birthday, billy. You're a great kid and you have awesome parents. Also," he added jokingly, "are you going to finish that cake? Because it currently doesn't seem finished and I love cake. Again, so touching, cake etc."

McNearney had tweeted, "One year ago I pushed this little fighter into the world. He's taught me true strength and joy. We promise to keep fighting for kids like you, sweet Billy. Thank you God for this light."

Last May,  Kimmel revealed on his show that his and McNearney's second child, William John Kimmel, had been born with a birth defect, tetralogy of Fallot with pulmonary atresia. "Basically the pulmonary valve was completely blocked, and he has a hole in the wall between the left and right sides of his heart," Kimmel told his audience. The newborn was taken to Children's Hospital Los Angeles for the first of multiple operations.

Kimmel in his monologue went on to express support for the Affordable Care Act, which disallows denial of coverage for pre-existing conditions.