The Skinny on Joel Madden

(Katy Winn/Getty Images)

One of the first goal’s of any new mother is to shed the extra pregnancy weight. And for rocker Joel Madden, it seems that getting slim after the birth of daughter Harlow has become a priority for this first-time pop.

While dining with Alan Philips, co-founder of the SKY Group, at Madame Tong’s in trendy Southampton, NY, over the Memorial Day weekend, Nicole Richie's babydaddy shared his secret to losing 15 lbs — He's been cutting out alcohol and instead sticking to water and sugar-free Red Bull.

It seems that fatherhood and being the best boyfriend ever fit for Joel. During his DJ stint at the opening party for La Playa, a partygoer tells OK!, “Girls were throwing notes and numbers his way, but Joel left with his brother Josh and flew back to L.A.” Another source adds, "He talked to Nicole on the phone no less than 15 times throughout the night."

Why the sudden departure? He had to take his baby girl to second birthday party for Gwen Stefani and Gavin Rossdale's son Kingston.