Hilary Duff‘s husband, Matthew Koma, has a hilarious relationship with his wife’s famous ex, Joel Madden.

The 35-year-old musician is on very good terms with the 44-year-old Good Charlotte star and his wife Nicole Richie, and used the singer’s birthday as an opportunity to poke a little fun at the superstar.

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“Happy birthday @joelmadden,” he wrote on his Instagram Stories, captioning a photo of the two of them outside together walking their German Shepherds, Roki and Xavi, adding: “Grateful for you and our friendship @joelmadden.”

The next photo included a throwback photo of Joel and Hilary at a Zac Posen fashion show in New York City in September of 2006, two months before they split.

“It’s not even that weird that you dated my wife @joelmadden. It just makes me feel closer to you,” he continued.

He then poste da drawing that reads “MATT + JOEL 4 EVA” as well as a photo of himself in a hairnet, playing a pink guitar while sitting next to Nicole.

“Also now feels like a good time to tell you about me and your wife @nicolerichie,” he amusingly added.

Fun fact: Hilary and Matthew are not only friends with Joel and Nicole, but they’re also neighbors!

“We actually hang out all the time. I was just in her driveway honking her to come drink wine with us the other day,” Hilary shared on WWHL recently, adding that they go on hikes together. “And you know what? It’s lovely.”

Check out some of the posts inside.

Matthew also trolled Hilary‘s fans asking for new music!