The Marvel Cinematic Universe recently celebrated its 10-year anniversary, as the conclusion of Phase 3 is already upon us. One of the franchise's first films was The Incredible Hulk (2008), starring Edward Norton.

The film was the lone time Mark Ruffalo did not play Bruce Banner in the MCU. But if it was up to the film's director, he would've had the role over Norton from the start.

In a 2013 interview with The Huffington Post, director Louis Leterrier explained that Ruffalo was always his first choice for the role. "When people are asking me... who's the better of the Bruce Banners -- both are great; both are fantastic -- but I actually wanted to cast Mark Ruffalo as Hulk," he said. "And Marvel was like 'No, you should get Edward Norton because he's more famous.'"

While Leterrier said that he enjoyed working with Norton, he believed Ruffalo was the right person for the role. However, Marvel didn't see it the same way.

"[Marvel] are the ones who wanted Edward -- and I was thrilled to meet him and work with him," said Leterrier. "I wanted Mark Ruffalo. And they were like, 'No, no, he just does smart, intellectual movies.' Which makes sense, then and there in his career."

But Leterrier's suggestion apparently stuck in the minds of Marvel's higher-ups, as Ruffalo was offered the role two years after The Incredible Hulk.

Besides his inability to not reveal spoilers, it's clear Marvel made a good choice with Ruffalo.