The campaign, which involves a mail pack being sent to 45,000 homes, is being handled by Proximity London and is the first piece of work by the agency as part of the 拢1m specialist stamp account it won last month.
Those being targeted are parents and grandparents of children who may be interest in stamp collecting as a hobby, tourists and lapsed collectors.
The mail pack has a Union Flag design shaped as a folded military flag and gives information on buying the set, as well as the history of the event.
The stamps will be available on June 7, ahead of the 176th event on June 11.
Supporting the direct activity will be national press advertising, posters and leaflets in post offices and a competition to win a luxury break in London.
The event to mark the Queen's official 79th birthday is her 52nd Trooping of the Colour where she will take the salute and review the troop as the Colours, a regimental flag of the Grenadier Guards, is paraded in a ceremony dating back to 1748.
Other activity includes Royal Mail's featuring a downloadable PDF giving instructions on how to perform some of the drills on display on the day.
An additional 25,000 bags featuring the slogan "I'm carrying a little bit of Britain" together with "goodies" including a flag, a postcard and a bottle of Highland Spring Mineral water will be handed out to crowds gathered at the event.
This latest campaign has been launched amid a furore over stamp prices this week following Postcomm proposals to limit price rises for first class stamps, thereby scuppering Royal Mail plans for a 60% hike.
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