QBE, which is an official partner of England Rugby, said the partnership with Easter begins immediately and runs until December 2011 – soon after the Rugby World Cup in New Zealand.
The deal will see the Number 8 become the face of the company’s rugby activity, attending key industry events.
At the end of 2009 QBE’s turnover was £6bn, making it one of the largest insurance firms in the UK.
“Nick was a great choice to represent QBE’s rugby sponsorship,” said Steven Burns, chief executive officer of QBE European Operations.
“Not only is he a superb rugby player and a great leader but he also shares many of QBE’s values, making him an ideal figurehead for us.”
Easter signed for Harlequins in 2004, winning the Harlequins player of the year award for two years running. He played for England in all six games at the 2007 Rugby World Cup.