"Yes," she confirmed after host Ellen DeGeneres asked if she's shared tips with Clooney. "It's going to be so fun. They are a great couple and they don't need advice from me or anybody else."
Roberts, who shares 9-year-old Henry and 12-year-old twins Hazel and Phinnaeus with husband Danny Moder, did confess Clooney might initially be overwhelmed.
"Nobody's there with you at 3 o'clock in the morning when you're just going, 'What are we doing? Where did they come from and when are they going?'" the star recalled of her own experience.
"You get through it and you figure it out, everybody does. It's trial and error and a whole lot of tears, and it's amazing," she said.
News broke in April that Amal is pregnant and expecting twins in June. Roberts, who has also co-starred with Clooney in Ocean's Eleven and other films, previously described Amal's relationship with the actor as "beautiful."
"Our lives have expanded in a beautiful way," she told ET Canada in May 2016. "Only when we're at their house, I see [Amal's] influence. In a beautiful way that all wives have, a kind of beautiful, loving influence."
Roberts will next star in an adaptation of the R.J. Palacio novel Wonder.