London-based New Zealand pop act Ladyhawke will headline a one-off charity concert in London for one person and their social network.

The Aug. 26 show at the Relentless Garage in Islington is to raise awareness for skin cancer, as part of Cancer Research U.K.'s SunSmart initiative. It will also feature New Young Pony Club and Bombay Bicycle Club.

To win tickets to the event, SunSmart is running a competition to find the person with the biggest guestlist for the event on social networks such as Facebook, Bebo, MySpace and Twitter. Online tools from the campaign's "Skindividual" Web site will help entrants to begin the process of building an event guestlist.

The 10 people with the longest guestlists by July 31 will proceed to the second stage of the competition, where they will need to submit a short film detailing why they should win. A special guest panel will make the final decision.

The Relentless Garage show has a capacity of around 500 people, so if the winning network is larger than this, it is up to the winner to select 50% of the audience and the other 50% will be selected at random by Cancer Research U.K.

Moby carried out a similar scheme last May for the launch of his "Last Night" (Mute) album, inviting fans to get the biggest guestlist together for his show at London's IndigO2 venue.