A troupe of dancers will send a semaphore message to the Queen from the roof of London's Royal Festival Hall as she passes by with the Jubilee pageant.
The South Bank Centre's artist in residence Lea Anderson has choreographed a new work which involves 30 dancers using flags to deliver their greeting.
The rooftop dancers will perform during the Thames flotilla in which dozens of vessels will form a procession on the river.
They will use red and yellow flags to spell out the message: "Happy Diamond Jubilee Queen Elizabeth, We Heart You."
It will be part of the centre's Festival Of The World which opens this weekend, coinciding with the Diamond Jubilee celebrations.
The three-month Festival of the World opens on Friday with numerous art installations and a pop-up street market with food from around the world.
The weekend will also mark the reopening of Jubilee Gardens, after a multi-million pound overhaul, to create the feel of an "English park".
Over the coming weeks, 4,000 artists will contribute to the Festival Of The World.
Outdoor works include a pair of robots made from recycled items which will scale the walls of the Hayward Gallery, a luminous cityscape made from plastic bottles and a sculpted baobab tree.