Eddie Murphy, Jennifer Hudson, Beyonce Talk about Dreamgirls with Oprah

The all-star cast of the upcoming movie, Dreamgirls, appeared on Oprah Winfrey yesterday.

Leading the way was Eddie Murphy, who said working on the film helped him deal with the painful end of his 12-year marriage because he could simply remain in character.

"I don't want to make it seem like I was Joe Actor," he said. "I was going through a big divorce then. ... It was really good because I had all that going on ... (but filming) would take me to a different place emotionally."

The Nutty Professor and Shrek star separated from his wife Nicole in 2005. Since about that time, Murphy has been dating singer Melanie Brown, aka Scary Spice of the Spice Girls.

The other stars of Dreamgirls also appeared on Oprah. Beyoncé Knowles, the film's lead, told Winfrey she lost 20 pounds for the role of Deena Jones (modeled loosely on Diana Ross) without being asked.

"I figured, in the '60s, Twiggy was the hot model, and Diana and Cher and all the legends were thinner than I am," she said. "So I decided I wanted to lose weight and make a physical transformation. And it was difficult because I love food. I love to eat. I did a fast â€" a master cleanse for 14 days. Everybody was eating Krispy Kremes around me. I was grouchy, but I did it, and I lost the weight."

Winfrey also welcomed former American Idol finalist Jennifer Hudson, who stars in the film as well. Hudson was criticized by Simon Cowell on the FOX show, but Cowell backtracked on Monday.

"I feel my criticism has probably had a significant part in your career, because the buzz on you is huge," Cowell told Hudson in a taped message. "I feel we had a very small part in what's happened in your life, and please thank me when you get your Oscar."