"I got to work with the best actors. They are so polished and so supportive. Usually, when you have Oscar-winning actors, sometimes they are not so supportive. But I could just watch and learn," the 25-year-old singer said in an interview published in the December issue of Prestige Hong Kong magazine.
"Dreamgirls," adapted from the Broadway musical, stars Oscar winner Foxx as a car salesman who worms his way into the Detroit music scene and becomes an impresario, orchestrating the crossover of black music to white mainstream culture.
Murphy co-stars as a flashy R&B singer. Knowles, "American Idol" finalist Jennifer Hudson and Anika Noni Rose play the Dreamettes, who start out as Murphy's backup singers but become a sensation on their own under Foxx's management.
"It was a great vibe," said Knowles, who fronted R&B group Destiny's Child. "Everyone was just happy to be involved in the movie."
Foxx won the best-actor Oscar for his performance in "Ray," and director Condon won an Oscar for adapting the screenplay of "Gods and Monsters."
Knowles won five Grammy Awards for her top-selling solo debut, 2003's "Dangerously in Love." Her second solo album, "B'Day," was released earlier this year.
Photos: American Music Awards Fashion Police
Photos: American Music Awards Show & Red Carpet
Photos: 2006 Holiday Films
Her screen credits also include "The Pink Panther" and "Austin Powers in Goldmember."
"It's exciting to do something new and put myself out of my comfort zone. I hope there will be more roles, and deeper roles, and this one will help prepare me for the future," she said.
"Dreamgirls," a DreamWorks and Paramount Pictures release, will be in U.S. theaters starting Dec. 25.