Chris Robshaw has been relinquished of the Harlequins captaincy to allow him to relieve the double dose of pressure on his shoulders.
Joe Marler has been handed the armband for the new Aviva Premiership season, and director of rugby Conor O’Shea believes both Quins and England will benefit from the change.
O’Shea said: “I have been speaking to him [Chris] about the dual role of captaining both England and Harlequins for some time.
“He has a massive year ahead of him and I feel that we should relieve him of some of the pressure, which will allow him to focus on being at his best for both club and country.”
He added: "We are extremely grateful to Chris for the four seasons that he captained the club, of which three were spent captaining both Harlequins and England.
“We want him to be at his best for Harlequins, win trophies here and also lift the World Cup next year. To do so we believe he needs to be fresh both mentally and physically, hence why we have made this decision now.”
Marler, who made his senior debut in 2009, said: "Firstly I want to pay tribute to how well Chris has done over the past four years, leading us through the most successful period we have had as a club.
New role: Joe Marler cannot wait to get stuck into his first season as Quins skipper
“It will be good to be able to take the pressure off him as he heads into a huge year with England.
"I'm really honoured to be asked to lead a special group like this and a great club, and I can't wait to get stuck in.”
O’Shea said: “I am delighted that Joe has agreed to take over the captaincy from Chris.
“He is a massively influential player and person within the group and will bring his own personality and style to the role, with the full backing of the entire squad and management.
"It is hard to believe that at just 24, Joe has already played over 100 times for the club and become a cornerstone of the England pack.”