Joseph Gordon-Levitt is getting great reviews for his new flick, "Don Jon," and he just handed out his own two-thumbs-up review to singer-turned-actress Lady Gaga.

Gordon-Levitt revealed that the Mother Monster has a cameo in Robert Rodriguez's "Sin City: A Dame to Kill For."

The actor opened up about the cameo to radio station Jam'n 94.5 days after he was spotted chatting with the Mother Monster during Sunday's MTV Video Music Awards. (She performed at the show and he presented Justin Timberlake with the Video of the Year Moonman.)

"She was in 'Sin City 2.' I did a part for [it]. Mr. Rodriguez asked me to be in, and Lady Gaga is in a scene of it. And I gotta say, she did a really good job," the actor said. "Like, she's a great actress. And I didn't know that. You know she came in and I was like, 'OK sure, they're having a huge pop star do a scene in the movie, I understand.' But then she came in and like, nailed it! She had her character down, and she was like a total pro and did a great job. I was really impressed. So it was good to see her again [at the VMAs]."

Gaga and JGL will be joined by A-listers like Josh Brolin, Eva Green, Mickey Rourke, Jessica Alba and Bruce Willis in the flick.

"Sin City: A Dame To Kill For" is slated to hit theaters August 22, 2014, but before then Gaga will not only drop her new album ARTPOP, but will also star in another Rodriguez flick, "Machete Kills."