Charm is an elusive quality, hard to quantify but essential when we talk about many of the actors that stay with us the most. And it's one that Lake Bell has in spades.

Of course, the 36-year-old is building an impressive career thanks to much more that, especially a knack for witty and observant filmmaking that she displayed in her acclaimed directorial debut "In a World ..."

The Manhattan native stars alongside Simon Pegg in the romantic comedy "Man Up," now playing at the Tribeca Film Festival, as a lonely woman who goes along with it when Pegg's character mistakes her for his blind date.

amNY spoke with Bell.

Let's talk about your British accent in the film. Did it take a lot of work?

Because I went to college there, I almost feel like I cheated a little bit. I had a bit of a shorthand within the accent. But also, you know, it's one of those things, I care about doing dialects and finding the authenticity in them so I can let go of them and then play the character. Especially in a characterization and on a set where I have to improvise.

How do you develop a seamless accent?

I started my training process in it a few months beforehand. ... By the time I landed in London, I was like, "I'm only going to exclusively speak in this Estuary accent." So that's what I did until wrap. And then at wrap, I came out to the crew as an American. I thought it was going to be an endearing, sweet gesture, to say, "Hey, look I want to tell you my real accent as Lake," "I care for all the hard work that you guys have put in," but in the end they looked at me as some sort of deceitful sorcerer.

The romantic comedy genre is hard to do well.

What I love about this character, it's not like she's so misanthropic that she can't operate in the world without functioning as a normal human. ... She's a realistic account of someone who is feeling cynical because it's rough out there. The whole movie has a sweetness to it and that's what drew me to it the most. It wasn't apologizing for being a romantic comedy. If anything it was embracing it deeply. There's so many romantic comedies out there that have a judgment about themselves.

You're about to direct your second film, "The Emperor's Children," in New York. What makes this city so great for cinema?

Like any location, it's all about the bones. You're always trying to find, when you're location scouting in any town, if it has good bones the production value goes up. New York is the best "bone" city in the country. ... It's filled with so much history and layers, architecturally but also energetically. It's constantly moving, so that makes it exciting. It's the best town in the world.

If you go: Man Up screens Thursday and Sunday at the Tribeca Film Festival.