Amy Schumer and Bill Hader star in the upcoming comedy Trainwreck–which Schumer wrote–and seem confident that the film, with Judd Apatow at the helm, will be a success. However, both of them were somewhat surprised when Apatow first championed them for the lead roles.

Schumer, who has been touring quite a bit since her appearance on Last Comic Standing in 2007, is also the star of her own sketch show on Comedy Central and has made a pretty big name for herself in Hollywood. But that doesn’t mean she felt she was ready to carry a film, even one she penned; as she says, she assumed that the studio would cast a glamorous actress, like Kate Upton, to take the lead while she sat on set with her “laptop and a messy bun, looking like a garden gnome”. That wasn’t Apatow’s vision.

“Had I gotten a phone call saying, ‘Oh, we’re going to have auditions for the role of Amy today,’ I would have said, ‘Yeah, of course,’ ” Schumer told the L.A. Times.

“But my entire world is based on the fact that we never do that to anybody. That’s like having someone else sing your song before you get to sing it,” Apatow said.

The film contains quite a bit of real-life subject matter for Schumer, including the fact that her father is battling multiple sclerosis.

“There is no denying that there is a lot of me in this movie. I, as they say, went there. It’s really personal. It’s about stuff I was struggling with and am constantly battling,” Schumer told Entertainment Weekly.

The biggest truth in the film, though, is that falling in love can be a very scary thing. For Schumer’s character–who lives a life full of barely-remembered one-night-stands until she meets Hader’s character–it’s terrifying.

“It’s scary to fall in love. I was falling in love with someone when I was writing it and it wasn’t even fun. It’s just terrifying. You’re just waiting to be hurt,” Amy Schumer said.