Ryan Gosling is one proud new dad!

The handsome star was all smiles as he hit the red carpet at the premiere of his new film, The Nice Guys, one day after news broke that he and long-time love Eva Mendes secretly welcomed their second child -- a baby girl named Amada.

WATCH: Surprise! Eva Mendes and Ryan Gosling Welcome Baby Girl

ET's Cameron Mathison spoke with the Oscar-nominated actor at the star-studded premiere, held at the TCL Chinese Theatre in Hollywood, California on Tuesday. While Gosling didn't go into detail about his new bundle of joy, he couldn't help but beam at the mention of his newborn daughter.

"We at ET want to say congratulations on your new baby girl," Mathison shared with the star. "That's a beautiful thing."

"Well thank you very much. Thank you," Gosling replied, smiling bright and waving to the cameras.

WATCH: Eva Mendes Fashionably Hides Baby Bump While Out With Ryan Gosling

Gosling, 35, and Mendes, 42, managed to keep one of the biggest secrets in Hollywood while expecting. The happy couple welcomed Amada on April 29 at 8:03 a.m. at Providence St. John's Health Center in Santa Monica, California, according to a birth certificate obtained by ET.

The high-profile celeb couple are already parents to 20-month-old daughter Esmeralda, who they welcomed in September 2014.

For more on Gosling and Mendes' new addition to their family, check out the video below.