Francois Louw says he is "honoured" to be Bath captain while lock Stuart Hooper recovers from an injured arm.
The 26-year-old South African flanker signed for the club in July and will fill in for Hooper who is not expected to return for up to six weeks.
The club's director of rugby Sir Ian McGeechan told BBC Bristol: "He's a strong character with huge respect amongst the squad."
Louw added: "It's a huge honour standing in for Stuart."
The Springbok continued: "He should be back in a few weeks, and the guys definitely miss him out there but it's a big honour to lead the guys and to have that role as captain.
"I didn't have much to think about. My only concern was having the boys back me in that role, that was the most important thing.
"You need to have everyone behind you and I certainly felt that way with the guys."
Louw skippered the side in Sunday's 18-13 Heineken Cup defeat by Leinster, and despite being yellow carded in the dying minutes McGeechan praised the former Stormers player.
"On the field he's a real competitor, and he was giving as good as he got at the weekend, challenging at the breakdowns but also good when the ball is in open play.
"He showed both sides of his game outstandingly at the weekend."