The 51-year-old actress and mother of 10-year-old son, Kieran, appeared on Good Morning America on Monday to promote her new series, Dietland, and shared some words of caution for her former E.R. co-star, who has 11-month-old twins, son Alexander and daughter Ella, with wife Amal Clooney.
"He doesn't need advice from me! He's married to Amal. She's a human rights lawyer," Margulies initially quipped. "We had a little email exchange and I was just asking how he's doing and he said, 'I just can't believe there's so much poop.'"
Margulies remembered telling Clooney, "And I said, 'Brace yourself my friend. They haven't even started eating solids yet.'"
Recalling her experience with diaper duty, the actress jokingly added, "My husband [Keith Lieberthal] and I used to call them sliders. They go up right up the back."
The former Good Wife star and Clooney portrayed one of the most beloved TV couples as Dr. Doug Ross and nurse Carol Hathaway on ER, which ran from 1994-2009. Now that the show is on Hulu, Margulies says she's being recognized for her breakout role all over again.
"I feel very lucky. Timing sometimes is everything," she mused. "Hulu has been streaming ER and I've been off that show for 18 years and all of a sudden this younger generation is saying, 'Wait. Aren't you Carol Hathaway?' And it's just throwing me back. It's amazing how that show just keeps living and I'm so grateful."
Back in May, Margulies exclusively told ET that Clooney taught her a big lesson during their time on ER.
"You're in it together. We're on a set with 100 crew members every day so if you're late, that means that they don't get to go home to their families," Margulies recalled on the set of Dietland. "That was the first thing I watched him teach everyone. It's important to respect and love your crew."