Johnny Sexton has taken over the Leinster captaincy from the retired Isa Nacewa.
The Ireland outhalf succeeds Nacewa, who walked into the sunset at the end of last season having lifted the Champions Cup and Pro14 titles in a dream final campaign.
Sexton, who has won 76 Ireland caps and has represented the Lions on 14 occasions, now inherits the role, with Rhys Ruddock as his vice captain.
"Johnny is a player and person who is always striving to improve and get better and he has driven incredibly high standards during his time at Leinster, where he has become one of the most decorated players in the game," head coach Leo Cullen said.
"He has already carried out the role of captain of the team on a number of occasions and we are very fortunate to be able to announce Johnny as club captain for the 2018/19 season as he is a player that greatly deserves this honour.
"He is hugely excited by the challenge of leading his teammates over the course of the season as we look to maximise the team’s potential.
"Likewise Rhys, we have seen him grow into an outstanding leader at Leinster and indeed he has captained Ireland on tour to Japan and again last season against Fiji and I think that this appointment today is further evidence of that growth.
"You couldn’t get two players that better represent the values and behaviours that we want to be judged on than Johnny and Rhys and I look forward to working even closer with them over the coming months."
Cullen's team travel to Montauban this Friday for their maiden pre-season game before taking on Newcastle Falcons at Energia Park seven days later.