Will Ferrell says he didn't know become a Christmas classic.

It's remained popular thanks to its combination of goofy humor thanks to Ferrell's presence in the cast, as well as genuine heart and warmth. Elf now ranks alongside the likes of Miracle on 34th Street, Home Alone and It's A Wonderful Life as a movie families watch together every holiday season. But it wasn't always that way, with Ferrell having said in the past that he initially feared starring in would destroy his career, as he didn't know how people would react to it. But, he's now revealed exactly when he realized it would be a success.

Related: Why Elf Is NOT The Most Over-Rated Christmas Movie Ever

Speaking to Off Camera, Ferrell says a test screening full of frat boys convinced him Elf would be successful. Ferrell says he didn't know if his core fans, who knew him from Saturday Night Live, would enjoy the movie. He says the first screening they did, for a family crowd, loved it, but his manager warned him the next screening was just frat boys. But it turned out they loved it, convincing Ferrell that Elf was the kind of movie people would put their cynicism aside for, turning it into a success. He adds that it "obviously came together" in the end. You can read his full thoughts below:

Prior to Elf I was known for a certain style of comedy coming off of Saturday Night Live. I’d just filmed Old School, which hadn’t come out yet. But I think I was known for edgier, provocative kind of comedies. So here I am in this Christmas movie. [I thought] "Oh my god am I just gonna get killed on this" you know. Are people going to just go “Wait, what is this premise, what’s going on here?" The first time we tested the movie we did two screenings. We did one that was more of a family-focused audience and it went great with them. And then my manager Jimmy called me and said: “Hey, so we just had the first one ,it went really well. But I’m looking at the crowd lined up for the second screening and it’s like a bunch of frat guys from USC and we might get eviscerated in this.” But it played for that audience too! That’s when we knew, oh well this could ... maybe this will work as one of those rare movies that works for everyone and you throw your cynicism aside. And it all obviously came together in a way that I never would have imagined.

Will Ferrell and Bob Newhart in Elf

It's funny to think that Ferrell wasn't sure Elf would be a success, given its status as one of the most-watched Christmas movies almost two decades later. But it shows just how much of a gamble the film was for the comedy star. If it hadn't connected with audiences, who knows where his career might have led. As it turns out, Ferrell has spent the past 17 years switching between more adult comedies like Anchorman and Step Brothers, and family fare like Daddy's Home.

While some movies have been more successful than others, there's no doubt Ferrell's longevity can be traced back to his star-making turn in Elf, proving it was even more of a success than anyone working on it could have envisioned. And Ferrell clearly is banking on his status as a Christmas movie star, having signed on to bring a A Christmas Carol to the screen with Ryan Reynolds. If it is half as successful as Elf was, it'll do well.

Next: How Elf Made Will Ferrell Look So Much Bigger Than Other Elves

Source: Off Camera