For nearly 70 years historians have debated whether Sir Hillary worn a Rolex or British-made Smiths timepiece of his wrist as he summited the world's highest mountain.
Both luxury watch-makers had supplied Sir Hillary and his sherpa Tenzing Norgay with watches ahead of their record-breaking climb in May 1953.
It's well-documented that when Norgay reached the summit, he proudly wore his Rolex Oyster Perpetual on his wrist.
Now a photograph has emerged which adds weight to the theory that Sir Hillary may have worn the British-made timepiece on his legendary climb.
The photo shows a dinner put on by Smiths watches for Sir Hillary just a few months before his successful expedition.
It could be the final clue to suggest Britain's last watchmaker did indeed beat the Swiss giant to the top of the world.
Estimated to fetch between £200 to £300 - The photo is being auctioned by Dominic Winter Auctioneers on October 6.
Cricket legend Sir Leonard Hutton was also amongst the group - who had sat down at the Savoy Hotel London on Tuesday October 20, 1953.
A menu from the event is also up for auction - signed by 28 people including ten of the Everest participants, three cricketers and various members of the watch and jewellery trade.
The picture will go under the hammer on October 6 as part of Dominic Winter's Printed Books, Maps & Documents auction.