Nick Clegg joked he was glad Boris Johnson had found "one party leader he is prepared to endorse in public" after the Mayor of London gave him his "fulsome backing" in a comment piece.
During his keynote speech at the Liberal Democrat party conference in Brighton, Mr Clegg said: "As a politician you get used to receiving criticism and praise from the strangest quarters.
"But even I was taken a little by surprise by the fulsome backing I received on the comment pages of the Daily Telegraph on Monday.
"The article praised my judgement, my policies, Miriam of course. But then I saw who it was by - a certain Alexander Boris de Pfeffel Johnson.
"Well, still, at least he has found one party leader he is prepared to endorse in public."
Mr Johnson hailed the Liberal Democrat leader as a "natural Tory" in an article for the Daily Telegraph and insisted people should be grateful he "laid down his political life" to form the coalition.
He also gave 20 reasons why everybody should be grateful for Mr Clegg, declaring: "Never mind the badgers – save the Cleggster from extermination!"