LOS ANGELES, ENGLAND - BRITISH actress Kate Winslet and comedian Tina Fey were early winners on Sunday at the Screen Actors Guild awards, which could produce surprises in a season dominated by 'Slumdog Millionaire' and 'The Curious Case of Benjamin Button'.

Winslet won the best supporting actress SAG award for her role as a German woman with a hidden Nazi past in 'The Reader'. Winslet won a Golden Globe earlier this month for her performance.

'Playing Hanna Schmitz was such a blessing, even though it made me completely insane,' she said.

Fey won best actress in a comedy for her show '30 Rock'. The show also took the top TV comedy prize - for best ensemble cast - and co-star Alec Baldwin won best actor in a comedy.

Angelina Jolie and her partner, Brad Pitt, Meryl Streep, Anne Hathaway and late Australian actor Heath Ledger were among nominees for top movie acting honors later in the evening.

The SAG Awards, in which actors reward their peers, are known for throwing curveballs on the path to Oscar glory.

'SAG has the potential to throw the Oscars into turmoil,' said Tom O'Neil, columnist for Web site www.TheEnvelope.com.

'The 'Slumdog Millionaire' actors are relatively unknown to American members of SAG, while 'Doubt' has all those respected A-listers who delivered really strong performances,' he said.

'Doubt', a story of suspected abuse in the Roman Catholic Church, leads with five SAG nominations, including the top prize of best ensemble cast, but it did not win a best picture Oscar nomination last week.

Penn, Rourke vie for Best Actor
Streep, who plays a vindictive nun in 'Doubt', and co-star Philip Seymour Hoffman are also nominated.

'Benjamin Button' leads the Oscar field with 13 nominations but has just three chances at a SAG award.

Quadruple Golden Globe winner 'Slumdog Millionaire,' the tale of a Mumbai slum dweller who makes good on a TV game show, has two SAG nominations for best ensemble cast and best supporting actor for Dev Patel.

David Poland, editor of Movie City News, thought neither 'Button' nor 'Slumdog' would win big on Sunday.

'I think the likelihood is that SAG won't go for 'Slumdog', Poland said. 'People admire 'Benjamin Button' but they don't love it. It is big and the acting is beautiful but it doesn't hit them emotionally.'

'Frost/Nixon,' which recounts journalist David Frost's interviews with disgraced US President Richard Nixon, and 'Milk' about slain San Francisco gay rights activist Harvey Milk, are also in the running for best ensemble cast.

Ledger, who has won a slew of posthumous awards for his role as the Joker in Batman blockbuster 'The Dark Knight,' is the front-runner for a SAG best supporting actor award.

Sean Penn, who plays pioneering gay San Francisco supervisor Harvey Milk, is seen as the strongest best actor challenge to Mickey Rourke's turn as a washed-up athlete trying for a comeback in 'The Wrestler'.

The strength of Hollywood's gay community could play well for Penn's chances, particularly after a bitter November 2008 referendum that outlawed same-sex marriage in California.

In television programs 'House', 'Boston Legal', 'Dexter', 'The Closer' and 'Mad Men' are competing for best TV drama ensemble cast. -- REUTERS