[1] Bellens graduated in 1978 as a commercial engineer at the Solvay Business School of the Université Libre de Bruxelles (Brussels).
In March 2003, Didier Bellens was appointed Belgacom's president and chief executive officer as the successor to John J. Goossens.
His position at the head of Belgacom almost ended in 2011 after a strong dispute with the company board and the Belgian federal minister for Civil Service and Public Enterprises, Inge Vervotte.
Bellens was a member of the Board of Directors of Belgacom ICS, the Telindus Group, Proximus, Scarlet SA, and Tango.
He was also advisor to CV Capital Partners and member of the International Advisory Council of the New York Stock Exchange.