London Zoo staff gave guests a little more than they paid for on Thursday morning - by running naked through the park.
Taking place in a month's time on 10 August, the fundraising event takes its name from the collective name for a group of Sumatran tigers ( a 'streak'), with ZSL London Zoo using the naked run to raise awareness for the plight of Sumatran tigers left in the world.
Anybody can enter the Streak for Tigers event, which sees participants run a lap around the zoo in the buff. It costs £20 for the registration fee and a pledge to raise a minimum of £150 for the cause.
Funds raised from the event go towards the zoo's international conservation work.
According to the Metro, previous funds from the event have been used to buy things like camera traps, which are used to monitor breeding and population evidence among wild Sumatran tigers.
The Sumatran tiger was listed as Critically Endangered on the IUCN Red List in 2008, as the population was estimated at 441 to 679 individuals, with no subpopulation larger than 50 individuals and a declining trend.
Major threats include habitat loss due to expansion of palm oil plantations and planting of acacia plantations, prey-base depletion, and illegal trade primarily for the domestic market.
For more information about the Streak for Tigers event, visit www.zsl.org