Costella passed away on 19 December 2008, leaving behind his wife Kate, whom he had been married to for nine months.
Costella began his career in marketing when he joined Conduit Business Solutions, a small business and systems consultancy, in 1998.
When the consultancy was bought by Razorfish in 1999, he took up an international role, helping to set up the company's Milan office.
Costella then moved on to TMW in January 2001, to help launch digitaltmw, the agency's new-media arm.
Working on blue-chip clients including British Airways, Diageo and Unilever, he was soon promoted to the role of director of strategy.
Richard Marshall, TMW's business development director, said: "Mick was a unique character within the agency, and his passion and joy for everything he did in his life was infectious.
"He will sadly be missed by many friends at TMW, and the wider industry will be a better place for having known him, even a little, and poorer for having had such a relatively short time to spend with him."