Freddie For A Day is a worldwide marker of the life of the Queen frontman that is celebrated around his birth date at the beginning of September.
This year, the charity party will take place at London's The Savoy Hotel on September 3 to raise funds for the Mercury Phoenix Trust.
The organisation, which was set up in Mercury's memory, continues to fight against the ignorance and infection of HIV and AIDS worldwide.
Last year's event saw Nicola Roberts, Fearne Cotton, Princess Beatrice, Princess Eugenie, Stephen Fry, Matt Lucas and Chris Evans all don iconic Freddie Mercury moustaches.
Also in attendance was comedian Russell Brand who commented: "Freddie is an idol to millions, me included. I work out to his music. If you're working out like Mr Fahrenheit, then you're going to be pumped."
Katy Perry, Dave Grohl and Adam Lambert have all supported the campaign, along with the Red Bull F1 team.
The Mercury Phoenix Trust was founded in 1992 by Queen's Brian May and Roger Taylor and Queen manager Jim Beach to help distribute money raised from the 1992 Freddie Mercury Tribute Concert for AIDS awareness.
The Trust has raised over $15 million (£9.5m) to help in the fight against AIDS worldwide during its 20 years.
Watch the music video for Queen's 'The Show Must Go On' below: