Camp & King has been named the new agency for the Energizer Holdings after a review.

TBWA had been Energizer's longtime agency, handling the business for more than 25 years. The shop did not defend the account. Camp & King will be fielding global work for the Energizer brand, as well as sibling brand Eveready.

Michelle Atkinson, chief consumer officer of Energizer Holdings, said Camp & King was chosen for the Energizer and Eveready accounts for "great strategy and strong creative," but mainly because of "their passion for our brands."

Energizer has long been known for the Energizer bunny, and while its future may have been unclear when the review started, it's now apparent that the bunny will keep on going and going. Ms. Atkinson said that part of the reason the agency was chosen because it had "a passion for the bunny...They were looking at taking the paradigms, keeping ones that will reinforce what the brand is about and letting the other ones go."

The bunny is iconic for older consumers, but part of Camp & King's mission will be "to make the bunny relevant and conversation-worthy today," she said.

Roger Camp, partner and chief creative officer at Camp & King, said that the agency's goal is to use the well-known mascot and "bring him forward" and introduce the bunny to younger people who may not recall the original ads.

"Part of what we want to do is take all the things that people love about the bunny and modernize him and to make him more relevant in channels like social, mobile and digital," said Jamie King, CEO.

A new campaign from Camp & King is expected to launch in the fall, likely in October.

"One of the things we expect Camp & King to help us do is connect in a more meaningful way with consumers," said Ms. Atkinson, "perhaps in a way that is more effective and really enables us to reduce our spending."

A key reason for calling the review was "we were looking for somebody who could be a smaller partner with a smaller team, with people who were fully integrated across our business, who could be more agile and nimble," Ms. Atkinson said. "With Camp & King, when we meet with them, we have all those people in one room and have one conversation."

Growth of batteries has been slow for more than a decade, leading Energizer to split last year from its personal care brands, which went into Edgewell, and rival Procter & Gamble Co. to undertake a similar process to spin off Duracell to Berkshire Hathaway.

"We're seeing flat volume," she said, but that doesn't mean Energizer plans to milk the business for profit. "Brands still matter in the category...People are still willing to trade up for a longer-lasting battery."

Energizer spent $43 million on measured media last year, according to Kantar Media. It spent close to that -- $39 million -- in the first half of 2015.