Former White House Chief of Staff Reince Priebus revealed that White House Chief Strategist Steve Bannon is someone who “only cares about” President Donald Trump’s agenda and thinks about his nationalist-populist platform “24 hours a day.”

“I will say that Steve is doing a great job,” Priebus said in a Friday evening CNN interview after Trump tweeted that former Department of Homeland Security Secretary John Kelly would be the new chief of staff. “He is a brilliant guy who only cares about the president’s agenda. He thinks about it 24 hours a day. Never quits.”

Priebus’ characterization of Bannon is consistent with accounts from former Bannon associates who often wondered if Bannon, known for working around the clock for issues he cares deeply about, ever slept because he cared so much about the nationalist-populist agenda that galvanized Trump’s voters and will be key to Trump’s reelection prospects.

Bannon has a whiteboard in his West Wing office with all of the promises—including building the “border wall”—that Trump made to his voters in 2016.

“My hat is off to Steve Bannon,” Priebus said.