Dermot O'Leary (born 24 May 1973, Colchester) is an English-born, Irish television and radio presenter. O'Leary established himself as a fixture on British television screens as presenter of Big Brother's Little Brother on Channel 4 and has since moved on to The X Factor on ITV. He has also presented on the BBC and has his own radio show on BBC Radio 2.

He is known internationally for introducing Michael Jackson to a large audience of fans in London in March 2009 in what turned out to be Jackson's final public appearance before his death, with the two sharing an affectionate hug.