On Tuesday, the Academy Award winner shared a sweet throwback photo of her holding her twins when they were babies.
"✨✨19✨✨," Roberts wrote in the caption of an Instagram post. "There are no words for the joy, the fun, the wild rumpus of life together. 💕"
Roberts shares Phinnaeus and Hazel with husband Daniel Moder. The couple also share son Henry Daniel Moder, 16.
Roberts has made a tradition of celebrating her kids' birthdays on Instagram. Last year, she took to the social media platform for Phinnaeus and Hazel's 18th birthday. She also shared an Instagram tribute the previous year for their 17th birthday.
While Roberts and Moder usually keep their family life private, Roberts loves to celebrate her children any way she can.
Last year, at the world premiere for her film "Ticket to Paradise," the actress wore a custom Alexander McQueen gown embroidered with her kids' initials, as well as her husband's initials.