Barry Bennett, the longtime Republican strategist who until recently was Ben Carson’s campaign manager, is now serving as an informal adviser to Donald Trump’s presidential campaign.

Bennett and Trump’s campaign manager, Corey Lewandowski, confirmed the relationship Friday.

Bennett described his unpaid role as one of counselor and resource to Trump’s top aides as they begin to prepare for a possible general-election campaign.

The Trump campaign’s alliance with a former rival was finalized last week during a private meeting at the billionaire’s headquarters at Trump Tower where Bennett offered to assist with planning.

“I believe Trump is going to win and it’s important that his campaign is ready for everything that is coming,” Bennett said in an interview. “I’m here to do what is needed. I’m not being paid and I’m going to be mostly focused on getting my business back up and running.”

A former adviser to Sen. Rob Portman (R-Ohio) and a campaign veteran, Bennett said he believes Trump has the chance to fundamentally shift American politics, as along as he does not trip up along the way.

“When I was at Trump Tower, I went over six or seven things they had to be worried about, in terms of the mechanics, party organization, and the convention. It wasn’t about strategy,” Bennett said. “My goal is to help them think through it.”

Bennett noted that after he departed Carson’s campaign after growing frustrated with the candidate, he connected with several other GOP campaigns, including with advisers to former Florida governor Jeb Bush and Sen. Ted Cruz of Texas. But Trump’s campaign was the best fit, he said.

Lewandowski and Bennett have known each other for years, going back to their days in Ohio politics.

“We appreciate the support of so many people who’ve been involved in the process and volunteers who have a wide diversity of backgrounds. We’re honored by Barry’s support,” Lewandowski said in a statement.