Naomi Watts is in her feels as she celebrates her son's milestone birthday. The actress, 56, shared a sweet message as well as photos of Sasha via Instagram on Friday, July 25, to ring in his 18th birthday. "Happy birthday sweet, darling @sashapeteschreiber," her post began. "18 today-and ready for the world! Cannot believe it. Have so loved watching you grow into the kindest, most wonderful young man. Thank you for making me a first time mum." Alongside the note, Watts posted new and throwback pictures of herself with Sasha.