Team London volunteers who worked at the 2012 Olympic Games will be back in business at a range of sport and large-scale events.
There will be 175 Team London Ambassadors at a National Football League fan rally at London's Trafalgar Square on Saturday and for the game between the New England Patriots v St Louis Rams at Wembley Stadium on Sunday.
Announcing the pilot programme for the volunteers, mayor Boris Johnson said he hopes they will help to cement the city's reputation as the world's capital for international sport and events following the London 2012 Games.
They will also work at Saracens Rugby Club home games when the team return to London in the new year at their newly-built stadium, Allianz Park in Barnet.
Teams of volunteers will also be rolled out for events at the O2, other locations around the city and during peak busy periods at Gatwick Airport next year.
More than 2,000 ambassadors have said they are interested in being part of the initial pilots, kicking off with 55 volunteers who will be working at the Eurostar terminal in central London until November 11.
During the London 2012 Olympics and Paralympics, 8,000 ambassadors were deployed to more than 40 locations, including major transport hubs and tourist hotspots to help provide guidance, information and advice on destinations and attractions to visitors.
Team London Ambassadors are aged between 14 and 85 and speak more than 40 languages in total.
Mr Johnson described the ambassador volunteers as "one of the undoubted highlights of the summer".