Joel: My Whole Life Centers on Harlow

It's no secret that Joel Madden and Nicole Richie are in love – and the Good Charlotte singer and father to Harlow says that strong family love is a big influence on his music.

"Obviously, when you’re in love, you write songs about it," he told OK! at Saturday night's Good Charlotte Album release party at Ecco Lounge in Hollywood. "It’s inspired some songs. It’s definitely something that I write about."

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Those songs inspired by his family are also a big part of their life, as Joel reveals he plays his music at home for his baby and girlfriend while they spend time together.

"My whole life is centered around her," he gushes about his daughter, "The only thing you really have is work and family."

His new role as dad, along with his rocker status, has definitely had an effect on Joel, as he admits of being a father, "Your whole life... your whole lifestyle changes."

Joel isn't just Mr. Serious Dad though, showing a bit of a sense of humor with reporters, saying she's "doing chemistry now," when asked what milestone Harlow had passed recently.

But seriously?

"She's doing great, she's growing up really fast."

By Katie Rhames