Comic and part-time Hollywood actor Brand has been in the spotlight for his views on politics, yet he would turn down the chance to put his ideas into practice at City Hall.
It seems Brand has less appetite for political action than his pontificating - done while promoting his new book, amusingly titled Revolution - would suggest.
Brand claimed he wanted "real change" and took a swipe at incumbent Johnson, while inadvertently appearing to suggest he would only be following in the Thatcherite Tory's footsteps.
When questioned on radio station Xfm about the possibility of a tilt at the mayoralty of the capital city, Brand said: "Absolutely not. We've already got a comic in the job. If you want a daft comedian running London, just leave things as they are. What I'm interested in is real change.
"You can see why people like him [Johnson]. He's a funny bloke, he's affable, he's got a nice way with him."
Johnson has recently heaped scorn upon Brand's less-than-coherent political opinions, by claiming that "total global chaos" would ensue were they rolled out by populations across the world.
Yet Johnson is one person who may be disappointed by Brand's uncharacteristic demureness on running for Mayor. The Tory leader in City Hall said he would be "thrilled" if Brand entered the race to replace him in 2016.