15 years after the movie’s release, costume designer Catherine Marie Thomas tells PEOPLE that her biggest challenge with Reynolds’ wardrobe was the denim

In 2009, when Ryan Reynolds was filming The Proposal alongside Sandra Bullock, his height created a bit of a challenge for costume designer Catherine Marie Thomas.

Specifically, the length of the 6′ 2″ actor’s legs created the challenge.

“At the time there wasn’t a lot of great denim with long inseams,” Thomas tells PEOPLE exclusively on the 15th anniversary of the movie, which was released on June 9, 2009. “I think it’s easier now for men with a 36-inch inseam to find pants. He’s got really, really long legs and is so tall. But yeah, that was such a specific thing with his wardrobe. It was pretty funny.”

Thomas needed the denim for the movie’s scenes shot in Alaska (which was actually Massachusetts). Reynolds’ character Andrew was taking his boss Margaret (Bullock) home to meet his family after she conned him into marrying her for a green card. For those scenes, the normally sharply dressed publishing assistant needed a much more casual wardrobe, which called for comfort.

“The Alaska scenes were fun with his wardrobe because we wanted to make him look comfortable because he was supposed to be around family and friends, plus he was doing masculine things like chopping wood,” Thomas says.

Even in those dressed-down scenes, though, Thomas says it was impossible to make him look “sloppy.”

“He’s so perfectly proportioned,” she says with a laugh. “He’s so handsome and, I mean really, truly, it’s really hard to make him look bad. We were really just trying to make him feel easy and effortless. In that regard, he was easy because he looks great in everything, and as long as he just looked casually effortless, it worked for us.”