Daniel Day-Lewis George Clooney Johnny Depp

Tommy Lee Jones Viggo Mortensen

There Will Be Blood

Age: 50

Nominated for: There Will Be Blood

The character: Daniel Plainview transforms himself from a Frontier-era silver miner into a self-made oil tycoon.

Previous Oscar wins: One (best actor for My Left Foot in 1990)

Previous Oscar nominations: Two

Acceptance speech: "I'm looking at this gorgeous thing that you've given me and... it seems to me that this sprang like a golden sapling out of the mad, beautiful head of [writer and director] Paul Thomas Anderson."

The critics said: "Daniel Day-Lewis's portrayal is not just the performance of the year but a creation of awesome proportions." (Wall Street Journal)

He said: "I can't for the life of me tell you why I felt an irresistible need to do this film."

Trivia: Day-Lewis disappeared from cinema screens for five years after 1997's The Boxer. He has refused to comment on speculation that he spent the period making shoes in Italy.

Michael Clayton

Age: 46

Nominated for: Michael Clayton

The character: A lawyer takes on the biggest and dirtiest case of his career and finds himself in a dangerous position.

Previous Oscar wins: One (best supporting actor for Syriana in 2006)

Previous Oscar nominations: One

The critics said: "Like Spencer Tracy, Gene Hackman, and others who have made acting on the big screen seem so easy while taking us on a journey that is far from simple, Clooney is the real thing." (Austin Chronicle)

He said: "The day after I wrapped Michael Clayton, I was on a plane to Darfur. There was something inside of me that made me want to go out and do something else."

Trivia: Clooney doesn't approve of suicide bombers. "Who wants seventy virgins?" he asked Rolling Stone magazine in 2005. "I want eight pros."

Sweeney Todd

Age: 44

Nominated for: Sweeney Todd

The character: Serial killer Sweeney lures victims into his Fleet Street barber shop before casually slitting their throats.

Previous Oscar wins: None

Previous Oscar nominations: Two

The critics said: "Depp is such a soulful presence he gives you a glimpse of this maniac's pain and pathos." (Newsweek)

He said: "Tim (Burton) didn't know if I could sing, and I didn't know if I could sing either."

Trivia: After singing on film, Depp says he has one last musical ambition: "If there's a chance of doing a duet with Barry Manilow now, then I'm in!"

In The Valley of Elah

Age: 61

Nominated for: In The Valley of Elah

The character: Hank Deerfield

Previous Oscar wins: One (best actor in a supporting role for The Fugitive in 1993)

Previous Oscar nominations: One (best actor in a supporting role for JFK in 1991)

The critics said: "Tommy Lee Jones is marvellous in the film. He has one scene in particular, a simple two-person encounter, that's as good as it gets in the realm of American screen acting." (Chicago Tribune)

He said: "Old Hank is the kind of character that I, personally, would dismiss... I looked upon him as typical of the sort of person who can be led by the nose by jingoistic headlines into a fraudulent war."

Trivia: He studied literature at Harvard University, where he shared a room with the future vice-president Al Gore during his second year. The two men are still friends.

Eastern Promises

Age: 49

Nominated for: Eastern Promises

The character: Russian immigrant Nikolai is a driver for an organised crime family based in London who finds his loyalty divided when a midwife begins investigating the death of a Russian teenager in childbirth.

Previous Oscar wins: None

Previous Oscar nominations: None

The critics said: "Mortensen's performance seemed so much bigger than the film surrounding it. That he manages the feat with so few wasted gestures puts him in line with the greats." (Boston Globe)

He said: "People will like to say that Eastern Promises is brutal, but the only reason they say that is because the scenes stick with them. They are realistic."

Trivia: Mortensen worked as a translator for the Swedish hockey team during the 1980 Winter Olympics in Lake Placid, New York.