Helena Bonham Carter and Liam Neeson are to be honoured at the 13th British Independent Film Awards on 5 December.
Bonham Carter, 44, star of the Harry Potter films, will get the Richard Harris Award, previously won by actors including John Hurt and Bob Hoskins.
She is also up for supporting actress for The King's Speech at the awards.
Neeson, 58, nominated for an Oscar for Schindler's List, will receive the Variety Award, previously won by JK Rowling and Helen Mirren.
Bonham Carter, who has starred in films including Howards End, Planet of the Apes and Fight Club, was nominated for a best actress Oscar in 1998 for The Wings of the Dove.
Last year's winner of the awards' outstanding achievement prize - introduced in 2003, a year after the death of Irish actor Richard Harris - was Daniel Day-Lewis.
Other previous winners include David Thewlis and Jim Broadbent.
Neeson's award, which recognises "an actor, director, writer or producer who has helped to focus the international spotlight on the UK", has previously been awarded to Richard Curtis, Michael Sheen and Keira Knightley.
The King's Speech leads this year's nominations with eight nods.
Gareth Edwards' sci-fi film Monsters has six nominations as do Never Let Me Go, an adaptation of Kazuo Ishiguro's 2005 novel, and The Arbor, a documentary about the life of troubled Bradford playwright Andrea Dunbar.