Hollywood actress Hilary Duff is keeping it friendly with at least one ex. The 'How I Met Your Father' star, 35, revealed on 'Watch What Happens Live' that she and ex-boyfriend Joel Madden have long been good friends, after "the whole world's mind was blown for a hot second" at her and husband Matthew Koma's dinner with Madden and his wife Nicole Richie.

"By the way, I have a good relationship with their whole family. I think people were (blown away). I don't know. We're neighbours. And we actually hang out all the time," she explained.

"I was just in her driveway, honking for her to come drink wine with us the other day," Duff added of Richie, 41, whom Madden, 43, married in 2010. "She wouldn't, she was asleep by 8."

She said now that they're neighbours, "We get them to hike with all the time," adding: "And you know what? It's lovely."

As per People, Duff previously posed for a photo last February during "date night" with Koma, 35; as well as Madden and Richie, and Pete Wentz and partner Meagan Camper. They were also joined by Pulse Music Group founder Josh Abraham and wife Gina.

"My husband is a giant troll, it's one of my favourite things about him," Duff noted. "Right when they moved in, for some reason Matt Photoshopped a picture of Joel and (brother Benji Madden) in a photo with me on Valentine's Day with like, 'Happy Valentine's Day, Honey'".

"So, this was before we started hanging out, and I think Joel and Nicole were like, 'Oh my god, they don't like us and we just moved in here next to them.' But no, they just know that Matt is a big troll and likes to have lots of fun," she said.