The station is using Vaughan, whose breakfast show launches on April 19, as the star of an ad campaign that will connect the station with Londoners.
It follows a year in which the city's top breakfast show lost 200,000 listeners.
Created by Delaney Lund Knox Warren, the musical ad tells the story of Vaughan's journey to work via various London attractions.
The ad opens with Vaughan waiting at a bus stop singing Maybe It's Because I'm A Londoner. It goes on to show him singing and dancing with passengers on the Tube, tourists at the Tate and roadsweepers in Trafalgar Square.
The ad ends with Vaughan arriving at work, where co-host Becky Jago asks "Good journey to work?", to which Vaughan replies "Oh, the usual."
The campaign begins on April 12 with outdoor activity including bus mega-rears to give the feel of a major announcement. The heavyweight TV campaign breaks on April 16 and will be supported by guerrilla activity. Media is by ZenithOptimedia.
Capital 95.8's marketing director, Carl Lyons, says the launch of Vaughan's breakfast show is the station's biggest opportunity to persuade new listeners to sample Capital since Chris Tarrant joined the station 17 years ago.
But the changeover is being seen by rivals as a chance to poach some of Capital's 2.3 million listeners. The biggest threat comes from Heart 106.2 , which last year briefly overtook Capital as London's most popular radio station.
Heart parent Chrysalis is investing an additional £1m in marketing over the next few months, a proportion of which will help Heart 106.2 and its LBC stations compete in the London market.
Steve Parkinson, marketing director for Heart 106.2, said the station is to launch a TV campaign next month, but denied it was in response to Vaughan's arrival at Capital.
He said Heart was concentrating on the strengths of its own breakfast show,which has recently secured guests including Jennifer Aniston and Halle Berry.