Joseph Gordon-Levitt

Joseph Gordon-Levitt

Joseph Gordon-Levitt thinks Scarlett Johansson's sex appeal is "off the charts."

The 'Don Jon' director and star knew he wanted the newly engaged actress to play his love interest in the movie long before he met her.

He said: "I didn't know Scarlett, but I spent more than a year with the image of her in my head playing this character. She couldn't not do this."

The 32-year-old actor said that Scarlett more than lived up to his expectations.

He told Men's Health magazine: "Look, Scarlett is a gorgeous, gorgeous woman, but if you just compare purely physical features, plenty of girls are just as gorgeous. But she creates this extra something. It's in her walk, her eye contact. The total package is just off the charts."

Scarlett recently got engaged to her French journalist boyfriend Romain Dauriac.

The 'Avengers' star was first linked to Romain, 30, in November 2012 and the couple announced their engagement after a whirlwind 10-month relationship.

Scarlett's spokesperson said: "I can confirm that Scarlett and Romain are engaged. They haven't chosen a date for the wedding."

Speculation about the actress' engagement began swirling last week after she was spotted wearing a large diamond ring at the Venice International Film Festival.