This is the first year Creative Effectiveness Lions will be awarded, and winning case studies will be available on warc.com following the awards ceremony.
The category was created to highlight the link between creativity and return on investment.
Judging criteria includes the measurable impact the campaign had on the client's bottom line.
Only entries that were either shortlisted or won their category in Cannes Lions 2010 can enter the new category.
The other Cannes Lions 2011 categories were opened for entries on Thursday January 27th, and must be sent by March 11th.
This year's Cannes Lions will be awarded at a ceremony on June 25th.
Dru, currently chairman of TBWA Worldwide, has a long history with the Cannes Lions, having headed the Film jury in 1982 and the Film and Press & Outdoor juries in 1998.
Philip Thomas, Cannes Lions ceo, said: "We believe that the new Cannes Creative Effectiveness category, which will ascertain a direct connection between creativity and effectiveness, will become one of the most important awards to win in the industry, especially in the eyes of the client.
"In Jean-Marie we have a hugely respected individual, and I can think of no better person to take the helm of the inaugural jury and doubtless set the standard for future years."
For other awards dates for your diary, please check Warc's Global Awards Calendar.
Latest case studies, including all the winners from this week's CASSIES Awards, can be found on the awards pages.
Data sourced from Cannes Lions/Warc; additional content by Warc staff