Benedict Cumberbatch has said he is an "idiot" after he described black people as "coloured" on US television.
The British actor said he was "devastated to have caused offence" following his contribution to a debate on the lack of diversity on British screens.
In a statement, the 38-year-old said: "I'm devastated to have caused offence by using this outmoded terminology.
"I offer my sincere apologies.
"I make no excuse for being an idiot and know the damage is done."
Cumberbatch had said on US talk show Tavis Smiley: "I think as far as coloured actors go it gets really difficult in the UK, and a lot of my friends have had more opportunities here (in the US) than in the UK and that's something that needs to change."
Anti-racism groups had described his use of the word "coloured" as "outdated" and said the term had "the potential to cause offence".
The British anti-racism educational charity Show Racism the Red Card said: "Appropriate terminology differs from country to country; for example, we know that in some countries the term 'coloured' is still widely used, and that in the US the term 'people of colour' is quite common.
"During our work with young people in schools throughout England, we discuss appropriate language to use when describing people of different skin colours and backgrounds and explain why the term 'coloured' is no longer the best way to describe someone."
The star also came in for criticism on Twitter, where one person using the handle SmallBee tweeted: "Cumberbatch used term 'coloured' why does that not surprise me. To use this term suggest to me he has no black people as friends #outoftouch"
Another, D'Arcy Lindsay, wrote: "Benedict Cumberbatch tries to stick up for black actors and then calls them 'coloured' #cringe"
In his apology the star of Sherlock and The Imitation Game said: "I can only hope this incident will highlight the need for correct usage of terminology that is accurate and inoffensive.
"The most shaming aspect of this for me is that I was talking about racial inequality in the performing arts in the UK and the need for rapid improvements in our industry when I used the term.
"I feel the complete fool I am and while I am sorry to have offended people and to learn from my mistakes in such a public manner please be assured I have.
"I apologise again to anyone who I offended for this thoughtless use of inappropriate language about an issue which affects friends of mine and which I care about deeply."
The actor is in the running at this year's Academy Awards for his portrayal of wartime code-breaker Alan Turing in The Imitation Game.
Cumberbatch and his fiancee Sophie Hunter, 36, are said to be planning to marry this spring and recently announced they are expecting their first child.