Ryan Gosling is "thrilled" to have a baby girl! Credit: Dave Allocca/Startraksphoto.com

Ryan Gosling is not only arguably Hollywood's hottest new dad; he's also one of the most excited! The Notebook hunk and his girlfriend Eva Mendes welcomed their first child together, a baby girl, on Friday, Sept. 12, and Gosling couldn't be happier — or more hands on!

"Ryan is thrilled it's a little girl," a source tells Us Weekly of the new father, adding that the Drive actor is, of course, "a little nervous" as well.

Although the couple have a nurse "helping out around the clock," another source tells Us that "Ryan hasn't left Eva's side" since Mendes and baby returned to her Los Feliz, L.A. pad a few days after the birth.

Lending a helping hand to the first-time parents as well are Gosling's parents, Donna and Thomas, his sister Mandi, plus Mendes' mom Eva Perez Suarez, and her sister Janet — with other pals stopping by with gifts, food and more.

"His family is now his number one priority," a source close to Gosling previously told Us. "He's accomplished everything work-wise that he had hoped and this is the next step in his life."