The ex-health secretary has come under fire for going on the ITV reality show, with his parliamentary whip being suspended.
But former politician Johnson, who went into the jungle himself a few years ago, suggested that Hancock could turn things around a bit.
"I watched last night... I thought he was superb," he said of Hancock's Busktucker trial.
"I cannot believe that Matt Hancock got 11 stars."
"He did prove himself and if redemption comes through suffering, he's on his way," he added.
Johnson said that he thought Hancock was "going to earn his spurs" in the competition, where he's in the camp alongside the likes of pop icon Boy George, radio legend Chris Moyles and Loose Women star Charlene White.
"I think he's going to go from strength to strength," he said.
"He may follow you, Toff."
And Johnson replied: "I think he could.
"I absolutely think he could win it."
Johnson and Made In Chelsea star Toffolo were campmates on the ITV programme in 2017. Johnson was the fifth celebrity to be eliminated from the competition and Toffolo went on to triumph and was crowned Queen of the Jungle.
Watch: Matt Hancock tackles 'terrifying' underwater task in second Bushtucker trial