Earlier in December Lewis Hamilton posted an image of himself and MotoGP to his Instagram profile and said: "Super excited to swap rides with the legend Valentino Rossi very soon... Watch this space guys."
The secret testing was to be held in Valencia, Spain on Tuesday, Dec 10.
Monster had organised the test event, which is being dubbed the 'invisible swap' since not a single social media post or any videos have been posted online of the six-times Formula 1 champion on Rossi's Yamaha M1 bike or of the latter in Hamilton's Mercedes 745kW F1 car.
And, that's a bit strange considering how both sportsmen are avid social media posters. Yet, that's how the organisers wanted it according to GPone's Matteo Aglio. (Read the original article here.)
Pirelli CEO Tronchetti Provera had urged Hamilton and Valentino Rossi to be careful as they swap their Mercedes and MotoGP machines at Valencia on Tuesday.
"We hope not to see extreme scenes," he said.
"They are two phenomena, two greats, but I hope they do not push too much. If the spirit they use today is the same as usual, there is a risk of seeing extreme scenes."
But, was it all just a publicity stint, or did the actual swap even take place at all? We will have to wait and see until something emerges.