Boris Johnson, mayor of London, will join Global Radio's speech station LBC 97.3.
Ask Boris will be a monthly phone-in on a Tuesday morning, co-hosted by the mayor, and will make up the final hour of Nick Ferrari at Breakfast.
Nick Clegg, deputy prime minister, presents a similar weekly Thursday morning phone-in, Call Clegg.
Johnson said: “The great thing about being on LBC 97.3 is that you get to hear what people are really talking about. Nothing is off limits as Nick Ferrari and his band of fellow assassins, LBC 97.3’s loyal London listeners, attempt to expose every pound spent, every promise made and I say ‘Quite right.’ If it matters to Londoners, I want to hear about it.”
Ask Boris begins on Tuesday 2 July from 09:00. Johnson can be found tweeting @MayorofLondon.