Smurfette added: “Why is Boris Johnson not a full time comedian yet?” And Mia said: “Boris will you marry me? pls bby x”
Mr Johnson was reelected Mayor by only a narrow margin over Labour rival Ken Livingstone in May.
But his popularity soared during the Olympics, particularly after he challenged Mitt Romney, the Republican candidate for the United States presidency, who had questioned Londoners’ enthusiasm for the Games.
David Cameron has been forced to deny that he finds Mr Johnson an irritant, brushing off a spate of opinion polls suggesting that the Mayor would be a far more popular choice than him to be Prime Minister.
But the Telegraph columnist continues to be a thorn in Mr Cameron’s side.
In his latest unhelpful pronouncement, he claimed that the Prime Minister, who was at the exclusive Eton College at the same time as him, had deliberately fluffed a question about the Magna Carta on the David Letterman show to avoid appearing elitist.
Classics scholar Mr Johnson said: ''I think he was only pretending. I think he knew full well what Magna Carta means.
''It was a brilliant move in order to show his demotic credentials and that he didn't have Latin bursting out of every orifice.''