Helen Mirren would not speculate on her Oscar chances The Queen clip

Mirren's portrayal in The Queen and Whitaker's Idi Amin in The Last King of Scotland were recognised as the best lead performances of the last year.

Their victories followed both actors' recent success at the Golden Globes.

Eddie Murphy and Jennifer Hudson won for supporting roles, while Little Miss Sunshine won "best ensemble".

Mirren, 61, was rewarded for her regal performances not only as Queen Elizabeth II in The Queen, but also as her predecessor in the TV mini-series Elizabeth I.

Emotional

The British actress would not speculate on her Oscar chances but said: "It's been the most incredible year for me, ever.

Forest Whitaker (centre) is building momentum for the Oscars

"That's been amazing at this end of my life."

Whitaker, 45, appeared very emotional as he picked up his prize for playing the Ugandan dictator.

"It means a lot to get an award from people that you work with and you're going to work with," he said.

The SAG judges have come to similar conclusions to their Oscar counterparts in recent years. Last year, three of the guild's four winning actors went on to take Oscars.

Eddie Murphy and Jennifer Hudson also followed Golden Globe success with SAG awards and look well placed to land Academy Awards in February.

Both won for their roles in the musical adaptation Dreamgirls.

Diverse

Hudson, who only two years ago was a failed contestant on the TV singing contest American Idol, was humble in the face of her meteoric rise.

Cruz described Volver as one of the best experiences of her life Volver clip

"Just thank you for noticing little old me and accepting me," she told the judges.

The Oscars ceremony will be held in Hollywood on 25 February. Observers say the line-up of nominees is one of the most diverse in years.

In other awards news, Oscar nominee Penelope Cruz was named best actress at the Goyas on Sunday - Spain's top film awards.

Her award was one of five prizes won by Pedro Almodovar's family drama Volver, which also picked up best director and picture.

Dark fantasy Pan's Labyrinth was the biggest winner of the night, scooping seven awards in total.