Jonathan Burley and Jim Bolton, the former HHCL creative directors, have joined Leo Burnett.
Reporting to the executive creative director, Jim Thornton, the pair will oversee the agency's creative output while producing work for all of its major accounts.
Burley resigned from HHCL in November last year. Since then, he has been linked with various agencies, including JWT.
His resignation from HHCL came just a month after the chief executive, Nick Howarth, left to take up the post of group chief executive at Clemmow Hornby Inge.
Burley denied that this had any bearing on his decision to leave. He said: "I decided that I didn't want to run a business any more. I just wanted to get back to being a creative director and putting out some really good work."
He added: "After years in a small agency, it's exciting to see such a big client list, with so many massive brands, at an agency that has recently produced great work. Anyone can create ads for little clients, but producing a memorable ad for a big client, such as McDonald's, is a real challenge."
Burley started his career at WCRS in 1993 and moved to HHCL in 1996.
In 2003, he was made HHCL's creative director, reporting to Steve Henry.
His clients included Sky, COI and Unilever.
Bolton began his career freelancing for agencies such as Saatchi & Saatchi and Grey, before joining HHCL in 1993. As well as working on clients including Mazda and Birds Eye, he created the celebrated "St George" ad for Blackcurrant Tango.
Thornton said: "This is a fantastic coup. It is evidence that all our hard work restructuring and rebuilding the agency over the past two years has not gone unnoticed."