Hegarty's knighthood, which he received for services to advertising, tops a stellar career during which the BBH co-founder has won golds and Grands Prix at every major advertising awards festival.
Hegarty said: "Whatever I've done, it's been within the structure at BBH, so it's a compliment to everyone there too. I couldn't have done it without them."
Hegarty, 63, started his career as a junior art director at Benton & Bowles in 1967 before moving to Cramer Saatchi as an art director in 1970, where he partnered Charles Saatchi. He was the creative director at TBWA\London for nine years between 1973 and 1982 before leaving to co-found BBH.
In 2005, Hegarty was inducted into the US Advertising Hall of Fame.