Johnson unexpectedly came out in support of Brand - who has been lampooned for suggestions he may stand to replace Johnson, despite previously calling for people not to vote. Brand has yet to comment publicly on the news.
Writing in The Telegraph, the Tory mayor says that criticism of “poor old Brandy Wandy” is unjustified, and that he sides with Brand because he "genuinely seems like a nice chap".
Brand has not confirmed his interest in running for London Mayor
Johnson claimed that much of the bad feeling towards Brand was simply motivated by jealousy: "of his success, his easy good humour, his string of beautiful and intelligent girlfriends, his Hollywood lifestyle, etc."
But the compliments turned out to be back-handed ones, as Johnson's piece was in fact using Brand to deal blows to his rival Labour party.
His true reason for approving of Brand, Johnson said, is that he is “such fantastic news for the Tory party”.
Brand's anarchic passion and his popularity with young people highlights how Labour has failed to engage one of its key groups: left-wing radicals, Johnson crowed.
Boris Johnson thinks Brand is "fantastic news" for the Tories
"After the long years of the post-crunch recession, there are many of a radical temper – especially young people – who are hoping for a prophet."
"As a phenomenon he is a sign of the disintegration of the Left and the weakness of Ed Miliband, and he therefore needs every possible encouragement."
Unfortunately for Brand, Johnson isn't so big a fan of his ideas. He slammed the comedian for calling for “total global chaos and destruction” and said his new anti-establishment book was "gibberish" and "bilge".
"Yes, it is bilge; but that is not the point," wrote the Mayor. "Who cares what he really means or what he really thinks? The crucial thing about Russell Brand is that he seems to be popular," said Johnson.
So Brand may not be able to count on John's vote after all if he does have designs on the Mayor's seat.
Brand’s reported plans to run for Mayor have not quite won the Twitter vote either. Commenters pointed out that Brand's beliefs that people should not vote could perhaps cause an issue if he campaigned for votes in a Mayoral race.
In an appearance on a BBC Radio 4 Start The Week programme on 'revolution' this morning, Brand responded to accusations that while he wanted to change the system, he hadn't laid out a plan for how to do this.
"It's been fascinating to watch the criticism, because in the book I talk a lot about successful methods and successful alternatives such as direct democracy... different mechanisms for controlling corporate power, different taxation models, different ways of organising work co-operatives..."
"One of the key tool of maintaining the status quo is to eschew that anything else is possible," he concluded.