Tatiana von Furstenberg and Francesca Gregorini may be first-time filmmakers telling a tale of growing up as privileged kids at boarding school, but their backgrounds suggest they know what they are talking about.

Von Furstenberg, daughter of fashion designer Diane von Furstenberg, and Gregorini, daughter of actress Barbara Bach and stepdaughter of Beatles drummer Ringo Starr, met at Brown University and have been inseparable ever since.

Now the two have co-written and directed Tanner Hall, a coming-of-age tale of two girls learning about life, love and friendship in theaters on Friday. Filmed in 2008, the ensemble cast stars Mara Rooney, who went on to star in The Social Network and the upcoming The Girl with the Dragon Tattoo.

Von Furstenberg, 40, and Gregorini, 43, sat down with Reuters to talk about the film, their friendship and growing up with famous parents.

Q: Why set Tanner Hall at a boarding school?

Von Furstenberg: Adolescence is about emerging into adulthood but still being dense with childhood. Francesca and I met during adolescence, so many of our stories went to that.

Gregorini: All the characters are composites of ourselves and experiences we've had or heard about at boarding school.

Q: One of the characters is conflicted about her sexuality. Francesca, as a lesbian, was this important to include?

Gregorini: It was such a part of my adolescence and my coming of age and that confusion. It was something I wanted in the movie and Tatiana fully supported it.

Q: Tatiana, did you ask your mom for help on the wardrobe?

A: She did the school uniforms, which was a large piece of the costuming. We had three weeks of pre-production on a very tight budget -- under $3 million, but probably closer to $2 (million). My mom really delivered for us.

A: How do you co-direct?

Gregorini: We had a kind of unspoken rule between us that whoever felt more passionate about a certain decision, then they got their way. We did many takes so if Tatiana didn't like something she would make a change and we'd go again.

Q: Was your friendship ever tested?

Gregorini: It was tested in editing. (laughs) There were a lot of lessons we had to learn.

Von Furstenberg: Our friendship was in the high risk area then!

Q: What happened?

Von Furstenberg: Francesca and I have very different work styles. She's very slow and thorough in combing through things, and I tend to just trust my judgment on the first throw up.

Gregorini: The editing process is the final word. It's your last chance to put together your movie. Deciding on takes was grating after a while.

Q: Do you think you will direct together again?

Gregorini: I'm the eternal optimist and I want to say yes. However I can guarantee you that we're both going to do a separate film each after this. We may come on to produce the other person's film because we're such an amazing support system for each other.

Q: Being so close, does that ever affect the other relationships in your lives?

Gregorini: Yes. I think it takes a very secure person to walk into what we have and find a place that feels safe and true and meaningful. We are very close and finish each others sentences and talk daily. We're sisters. I consider Tatiana family. She's not a negotiable piece of my life.

Q: How does your past influence you as filmmakers?

Von Furstenberg: In pre-production, we're taking executive risks, signing contracts with guilds and unions and overnight having an entire team that we need to lead. I'd been around risk taking executive decisions my entire life so it felt natural. I had not awoken that part of me before.

Gregorini: Yeah, we all saw this side of her come to the fore, which was very necessary to navigate the waters that we were heading into.

Von Furstenberg: With Francesca, I think that because she grew up with a James Bond girl her as her mother, there's a certain sensibility in having been on film sets as a young child and backstage with the Beatles. She knows how to make things larger than life, which is why you want to see a movie.

Gregorini: When the bar (with your parents) is that high, you're not going to cross it. So it's kind of liberating because you get to be yourself and do what you want to do. No matter what achievements I do in my life, I'm not going to be a Beatle. And that's okay (laughs) I made my peace with that early on and find liberation in being the artist that I am.