The Runescape street party takes place on June 2, and will be preceded by a visit from the Queen in a unicorn-drawn golden carriage.
To further celebrate the event, the developers will introduce a collection Jubilee-themed content.
In addition to British cuisine, such as fish 'n' chips, steak and kidney pies and cream teas, characters can also nab unique treasures, royal souvenirs, Corgi dogs and Union flags.
"The Jagex team and I were incredibly honoured last year when we were recognised for our continued success over the past decade by receiving the Queen's Award for Excellence," commented explained Jagex CEO Mark Gerhard.
"We thought it was only appropriate to return our appreciation and admiration by immortalising the Queen's monumental 60-year achievement by providing an online platform for hundreds of millions of people around the world to come together.
"Friends and family will share in the fun and celebrations of this very special day celebrating her Diamond Jubilee, by hosting what may be the first, but certainly will be the world's largest, virtual street party. Everyone is invited, especially her Majesty."
Runescape is a free-to-play massively multiplayer online role-playing game launched in 2001.
It has over 156 million registered accounts and is recognised by Guinness World Records as the world's most popular free-to-play MMORPG.
Developer Jagex unveiled a new website and logo for its popular free-to-play online role-playing game last November.
The redesigned website contained an array of new tools and features, including a new community-editable Runescape wiki and a dedicated events section.
It welcomed a brand new 'Troll Warzone' tutorial area last month.
Watch Runescape's 'Troll Warzone' trailer below: