Johnny Sexton vacated the role following his retirement from the sport last month.
Leinster have confirmed the appointment of Garry Ringrose and James Ryan as joint captains.
The pair replace Johnny Sexton, who retired following the World Cup.
Both Ringrose and Ryan returned to Leinster training earlier this week following their exploits with Ireland in France.
Leinster are next in action against the Dragons in the URC this Sunday.
Kick off at Rodney Parade is set for 1.15pm.