"In Her Shoes" (search) begins when the n'er-do-well character played by Cameron Diaz (search) gets kicked out of her responsible sister's apartment and winds up going to live with her long-lost grandmother, played by Shirley MacLaine (search).

Sounds like a weepy, doesn't it? But everyone involved insists this family comedy, which opens this weekend, is not just a "chick flick."

"It's not a chick flick, that's the key. This is a story about people, these are human beings, there's parts to each of these characters that everyone can relate to. Male or female," Diaz told FOX News.

"Ultimately I think the film is just about family, and it has more of a universal tone in that respect," added co-star Toni Collette (search).

For Diaz, working opposite a Hollywood legend like MacLaine meant getting over being starstruck.

"We had rehearsal period for a while, so I got used to [not gawking at her as much]. Oh my God! I actually had a little time to understand that I had to work with her. And I had to say the other part," she said.

And at 71, MacLaine has one simple secret to her success.

"If you love the process, than you have a happy life. That's the secret to my longevity. I won't do anything that makes me unhappy, other than exercise."

FOX News' Mike Waco and Trace Gallagher contributed to this report.