Julia Roberts marked her twins' milestone 21st birthday in the sweetest way. Roberts, 58, shared a rare throwback baby photo via Instagram of daughter Hazel and son Phinnaeus to celebrate the sibling duo turning 21 on Friday, November 28. In the picture from when they were infants, Hazel and Phinnaeus sat side by side in high chairs while eating cake. Blue and pink gift bags sat on the table behind them.