'Material Girls'

Hilary Duff, right, and her sister, Haylie, pose for photographers at the New York premiere of their film, "Material Girls," on Aug. 14, 2006. The sisters have collaborated musically in the past, but their new film is the first time they can be seen together on the big screen.

Haylie Duff poses for photographers at the New York premiere of her film, "Material Girls," on Aug 14, 2006. The comedy opens in theaters on Aug. 18.

Hilary Duff poses for photographers at the New York premiere of "Material Girls" on Aug. 14, 2006.

Sisters Haylie Duff, left, and Hilary Duff pose for photographers at the New York premiere of their film, "Material Girls," on Aug. 14, 2006. "It actually felt really normal, and it was really easy for us," Haylie said of working with her sister. "We are really close in real life. We felt lucky that we had the opportunity to do it."

Haylie Duff, left, and Hilary Duff attend the New York premiere of "Material Girls" at Chelsea West Cinemas on Aug. 14, 2006. The sisters star as heiresses to their family's cosmetics fortune.

A poster stands at the premiere of "Material Girls" at New York's Chelsea West Cinemas on Aug. 14, 2006. The film, which opens Aug. 18, stars sisters Hilary and Haylie Duff and Angelica Huston.

Actress Haylie Duff walks the red carpet at the premiere of "Material Girls" at Chelsea West Cinemas in New York on Aug. 14, 2006.

Actor Sebastian Stan attends the premiere of "Material Girls" in New York on Aug. 14, 2006.

Sisters Hilary and Haylie Duff were all smiles as they arrived together at the New York premiere of their film, "Material Girls," on Aug. 14, 2006. The film opens Aug. 18.

Actor Obba Babatunde attends the premiere of his new film, "Material Girls," at New York's Chelsea West Cinemas on Aug. 14, 2006.

Hilary Duff attends the premiere of "Material Girls" at New York's Chelsea West Cinemas on Aug. 14, 2006. Duff became a star when she played the title role in the successful television series "Lizzie McGuire."

Director Martha Coolidge attends the premiere of "Material Girls" at Chelsea West Cinemas in New York on Aug. 14, 2006. For the movie, Coolidge asked Hilary and Haylie Duff to help her better understand the lives of two young Hollywood women. The sisters obliged, taking the director to nightclubs in Los Angeles.

A glam Hilary Duff walks the red carpet at the premiere of her new film, "Material Girls," at New York's Chelsea West Cinemas on Aug. 14, 2006.

Actress Ellen Muth attends the premiere of "Material Girls," starring Hilary and Haylie Duff, at Chelsea West Cinemas in New York on Aug. 14, 2006.

Big sister Haylie Duff poses for photographers at the New York premiere of her film, "Material Girls," on Aug. 14, 2006. She shares the big screen with her younger sibling, Hilary. Haylie, who is currently starring on Broadway in "Hairspray," wrote two songs for Hilary's first solo album, "Metamorphosis."

In this photo provided by MGM Pictures, Tanzie Marchetta (Hilary Duff) and sister Ava (Haylie Duff) attend the tribute to their late father in "Material Girls." The sisters portray heiresses to a multimillion-dollar cosmetics company.