A Banksy painting of a young boy ditching his Batman and Spider-Man action figures for one of a caped superhero nurse could raise more than £3m for the NHS.
The Street artist is offering the 'Game Changer', as a "universal tribute" to staff.
The image, which measures 1m (3ft) x 1m, was hung in collaboration with the hospital's managers in a foyer near the emergency department.
Auction company Christie's said the painting "offers an image of hope" and represents a "personal tribute to those who continue to turn the tide of the pandemic".
Game Changer will be seen outside the hospital for the first time, hanging in a window at Christie’s headquarters in London from 8-15 March. It will be sold at the auction house’s marquee art evening sale on 23 March with an estimate of £2.5m-£3.5m.
Katharine Arnold, of Christie's, added: "Game Changer is a universal tribute to all those fighting worldwide on the front line of this crisis.
"The work pays tribute to the strength and resilience of those who have demonstrated true leadership throughout the pandemic, the staff of our vital NHS", she added.
She also described Game Changer as a "beacon of light for the staff and patients" at the hospital.
Its sale is following a pattern with Banksy selling a triptych at Sotheby’s last summer to raise money for a hospital in Bethlehem.
Mediterranean Sea View 2017 was three traditionally framed romantic-era seascapes on to which Banksy had added washed-up lifebuoys and lifejackets, making a statement on the global migrant crisis. It sold for £2.2m.