Lewis was ready to give Mike Tyson a rematch, but the former undisputed champion said he is not ready after recording a first-round knockout of Clifford Etienne on Feb. 22.
Without a big-money fight against Tyson, Lewis (40-2-1, 31 KOs) was expected to face Ukrainian Vitali Klitschko, who is ranked No. 1 by the WBC. On Thursday, however, Lewis announced he will fight Johnson, with Tyson expected to meet Oleg Maskaev on the same card.
The 37-year-old Lewis has not fought since recording a dominating eighth-round knockout of Tyson last June. Although Lewis overmatched Tyson, he still believes a rematch is what many fans would like to see.
"There's still a lot of Tyson fans out there and a lot of disbelievers from the first fight. They feel Mike Tyson wasn't right and something went wrong," Lewis said during a conference call.
Johnson (34-1-1, 25 KOs) lost to former WBA heavyweight champion John Ruiz last July, when he was disqualified in the 10th round for excessive low blows.
Since that loss, Johnson has knocked out Jeremy Bates and Lou Savarese. The 30-year-old Johnson is unconcerned that he will not be fighting for the WBC title.
"I got the opportunity to show the world that Kirk Johnson is the best heavyweight on the planet. I don't care," Johnson said. "I fought for a major belt. These belts, they make a difference, but then again they don't make a difference. Once I beat Lennox Lewis, they'll know I beat the man that beat the man that beat the man."
Still the biggest draw among heavyweights, Tyson (50-4, 44 KOs) has never lost a non-title fight. His license is suspended in several states, but he is expected to be able to obtain one in California.