Nicole Richie and Joel Madden React to Benji and Cameron Diaz Naming Their Son Cardinal (Exclusive)

Nicole Richie and Joel Madden aren't taking credit for kickstarting bird names in the family. The couple are parents to 16-year-old daughter, Harlow, and 14-year-old son, Sparrow. 

Joel's twin brother, Benji Madden, and his wife, Cameron Diaz, recently announced that they welcomed their second child — a son named Cardinal. 

ET's Cassie DiLaura caught up with Nicole and Joel at the premiere of Nicole's new film, Don't Tell Mom the Babysitter's Dead, where the topic of the family bird names came up.

When asked whether Benji spoke to Joel about choosing a bird name for his son, Nicole tells ET, "I didn't ask, but I really don't think they did. I think it's just a twin thing -- who knows?" 

Nicole adds that "everyone's amazing" amidst the new addition.

ET also spoke with Joel on the red carpet at AMC The Grove in Los Angeles about his nephew's name. 

"It was a surprise to all of us. We're all very happy though," Joel tells ET. 

Cameron and Benji announced the birth of their son, Cardinal, in March. 

"We are blessed and excited to announce the birth of our Son, Cardinal Madden❤️🙏He is awesome and We are all so happy he is here!" the couple wrote on Instagram. "For the kids safety and privacy we won’t be posting any pictures- but he’s a really cute ☺️We are feeling so blessed and grateful 🍀."

Cardinal joins big sister, Raddix, 4. 

At Tuesday's premiere, Joel adds that he's "very proud" of Nicole's turn as Rose in the remake of the 1991 comedy starring Joanna Cassidy in the same role. 

"First of all, I'm a diehard of the original," Nicole tells ET. "This is truly who I am in my soul without ever thinking I would get the opportunity to play Rose. So when this came my way, I was like, 'Oh my god, this is too good to be true.'"

Nicole and Joel walked the red carpet with their kids, and Nicole says that her R-rated comedy is in fact a movie for the whole family. 

Insists Nicole, "The movie is rated R, but it really is a family movie."

Don't Tell Mom the Babysitter's Dead is in theaters April 12. 

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