Eva Mendes is dog-sitting for Ryan Gosling's pet pooch George.

The 38-year-old actress - who has been dating the 31-year-old star since September - is believed to be hoping to prove to the hunk that she is serious about their relationship by taking care of his beloved canine companion while he films new movie Only God Forgives in Bangkok, Thailand.

"He was going to have his friends watch George, but changed his mind at the last minute. That's a huge deal to him. He wouldn't leave that dog with just anyone," an insider said.

Eva recently admitted working with Ryan on The Place Beyond the Pines was one of the best creative experiences she has ever had, as he was her "dream co-star."

"He's your dream co-star. I have never felt so creatively satisfied on a film. He's amazing," she said.

The Hollywood heartthrob is already believed to have introduced the brunette beauty to his mother, Donna, when the trio went to see a movie in New York together. "They all hung out and went to the movies together. Ryan and Eva seemed very happy," a source said at the time.