And I couldnt shake it, couldnt stop thinking about it.

I started thinking about writing it as a film and as a comedy.

I had to change some elements.

I started thinking about my buddy Owen [Wilson] filling in, and then it started being funny.

Its actually my favorite scene in the movie, and Owen is amazing in this movie.

Read on for more from Harrelson about the making ofLost in London.

ENTERTAINMENT WEEKLY: How did you convince Owen Wilson to be in the film?

Because this could have gone horribly wrong.WOODY HARRELSON:Oh, yeah.

Right up to the last minute, I thought itwasgoing horribly wrong.

The sound was really problematic, and especially if I was inside a car.

Well, theres like five vehicles in this movie, because thats really the way things happened that night.

There was all kinds of [laughs] time inside vehicles.

None of that would work, and a lot of other sound stuff wasnt working.

We had about 26 sound people on this.

These guys had done everything, from huge movies to the marathon to the Olympics.

All kinds of big things.

And they all said this is is the hardest job they ever had in sound.

Somehow on the night, that came together.

Lost in Londonfeatures a cameo from Willie Nelson, who appears in a dream sequence.

But then I started thinking about a dream sequence.

I called Owen to talk to him about something, and Willie was there.

So I said, How you doing, Willie?

and he says, Good, but you dont have a part for me in this movie?

[I said,] Do you really want to be in it?

And he said, Hell, yeah, I want to be in it.

Thats how that happened.

But mostly its true to life, its what happened on the night.

The Woody Harrelson you portray in the film is not always a very attractive person.

Its a real question of whether or not in the end the audience will like me.

In some ways, the story is the story.

So I figure if they dont end up liking me, thats fair.

In the end youre like, Well, hes telling the truth, you know.

So it was better if the other characters coming in were the ones making you laugh.

Id be the bass note, and theyd be the other notes around that.

Has Wes Anderson seen the film?

Actually, I ran into him in London.

I was there prepping, and then in comes Wes!

Im like, Oh my God, Ive got to go talk to him.

But I want you to know its just for laughs.

And he says, Okay, yeah, no problem.

And then he watched it and really liked it.

At one point in the film, Woody calls Bono.

Is that really Bono on the other end of the line?Yeah, thats Bono.

Thats really all from Bono, when he was feeling under the weather.

So, pretty cool of him, man.

Lost in Londonscreened live in cinemas.

They really kind of felt the theater element of it.

It was just a mind-boggling just the logistics were quite daunting.

Thats why Im surprised that I decided to try something like this, my first time as a director.

I guess maybe that way, from now on, itll be a little easier.

ThisSolomovieandLost in Londonare coming out the same day.

One might do a little better than the other.

Lost in Londonis now availabe to watch ondigital platformsand VOD.

Watch the films trailer above.