The following are brief profiles of the best actor nominees:
HUGH JACKMAN, Les Miserables - The Australian actor, 44, is no stranger to the Oscars, having hosted them in 2009. But he had to wait till now for his first Oscar nomination for playing the role of the escaped convict anti-hero at the centre of the dramatic hit musical Les Miserables. First coming to the fore as an action super-hero in the X-Men series, his other hits include Van Helsing and The Prestige.
BRADLEY COOPER, Silver Linings Playbook - This is Cooper's first Oscar nomination, earned for playing the bipolar character at the centre of the quirky romantic comedy Silver Linings Playbook. Cooper, 38, first came to fame in the TV series Alias, and his recent film hits have included The Hangover, The A-Team and Limitless. In 2011 he was named People magazine's Sexiest Man Alive.
DANIEL DAY-LEWIS, Lincoln - Day-Lewis's remarkable portrayal of US President Abraham Lincoln has been generating Oscar buzz from the word go. Famous for his devotion to his roles, the British-Irish actor, 55, has won two previous best actor Oscars for My Left Foot in 1989 and There Will Be Blood in 2007.
He is considered the hot favourite this year.
JOAQUIN PHOENIX, The Master - A former child actor with a love-hate relationship with Hollywood and stardom, Phoenix, 38, is an intense and meticulous actor with two prior nominations - Best Supporting Actor for Gladiator in 2000 and Best Actor for Walk the Line in 2005.
His current nomination is recognition of his role as an alcoholic military veteran who is taken under the wing of a cult guru.
DENZEL WASHINGTON, Flight - One of the most talented and reliably popular stars in Hollywood, Washington earned his chance for a third acting Oscar for his role as an airline pilot whose heroics are threatened by drug and alcohol abuse. Washington, 58, previously won Best Supporting Actor for Glory in 1989 and Best Actor for Training Day in 2001.