From one parent to another! Shortly before Josh Peck and wife Paige O'Brien welcomed baby No. 2, his How I Met Your Father costar Hilary Duff gave him a useful — and adorable — tip. "She's got three kiddos and she gave me this great advice when Shai was about to be born," the Drake & Josh alum, 36, exclusively told Us Weekly on Wednesday, March 22, while promoting his partnership with Enfamil. "She's like, 'When you bring Shai home from the hospital, have Max give Shai a tour of the house. Show him all of his favorite spots in his playroom and whatnot, but just so he really feels like he's welcoming Shai into the family home.'" Peck and O'Brien, 32, announced the birth of son Shai, now 5 months, in October 2022. The duo — who tied the knot in 2017 — welcomed son Max, now 4, in December 2018. Josh Peck and Hilary Duff Shutterstock (2) Duff's advice seems to have worked, because O'Brien said Max "did an incredible job" once his little brother arrived. "We were a little worried that he had had so much time and attention on him for so long that [he was] gonna be in for a rude awakening when this baby comes in," the cinematographer told Us. "He didn't have any jealousy issues or anything like that." The filmmaker added that another friend advised them to "prioritize" Max so that he didn't feel left out. "We really wanted to make sure that we were having him help as much as he could help — having him help us make decisions when it came to the baby," O'Brien recalled. "We were all working as a team so he felt like it was all of us and not just me always with the baby." Peck, for his part, spent a lot of time gushing over his children while at work, especially with Duff, 35. The Younger alum shares son Luca, 11, with ex Mike Comrie and daughters Banks, 4, and Mae, 23 months, with husband Matthew Koma. "We're like two extremely proud parents," the Grandfathered alum told Us, adding that he and Duff swap plenty of parenting stories on set. "We are completely in love with our kiddos, and I think she's super impressive. ... Some parents have their kids and then their focus becomes back on their work and their life, and I think for us we are just enamored by them. We're always joking with each other about how many kids we're gonna wind up having." While the former Nickelodeon star and his wife aren't sure they're done having kids, they think they're set for the near future. "If you were to ask me a couple months ago, I'd be like, 'Yeah, I could do this all day,'" O'Brien said. "And then you're in the middle of a sleep regression and you're like, 'I think I'm good.' At least for a while. So, I don't know, it's kind of up in the air for us." Josh Peck and Hilary Duff on 'How I Met Your Father'. Patrick Wymore/Hulu The duo have somewhat settled into a routine as a family of four, but they partnered with Enfamil's Family Beginnings program to make sure other new parents get all the support they can. The program offers coupons, free samples and educational resources to help moms and dads raise their kids with as little stress as possible. "Paige and I are team 'support new parents' as opposed to 'scare new parents,'" Peck explained. "I remember a friend of mine said, 'Don't worry about anything. It's only gonna be great. And any minor inconvenience, any lack of sleep will be so overshadowed by how cool this kid is.' And so a program like Enfamil Family Beginnings really spoke to us because that's exactly what they're doing. They're supporting new parents." O'Brien, for her part, started using Enfamil formula with Max when she wasn't producing enough breast milk. "With Shai we went straight to Enfamil from day one in the hospital, and it's just been great for us," she added. "The second time around it was a little easier to get it in my head that this is totally fine, I've done it before and this is what's right for our family. ... It's OK to pivot and to figure out a new journey for yourself."Sign up for Us Weekly's free, daily newsletter and never miss breaking news or exclusive stories about your favorite celebrities, TV shows and more! With reporting by Christina Garibaldi