With a combined total of 15 world championships and with both staking claims to be the greatest of all-time in their respective fields, Lewis Hamilton and Valentino Rossi came together for one of the most anticipated ride swaps in racing history on Monday in Valencia.

The long-awaited test was arranged by Hamilton and Rossi's mutual sponsor, Monster, giving the duo a chance to sample each other's machinery.

Hamilton was able to complete his first test on a MotoGP bike in the running at the Circuit Ricardo Tormo in Valencia, Spain, adding to his growing experience on two wheels after a previous run-out on a Superbike last December. The running saw Hamilton became the first F1 driver to try out a MotoGP bike since Fernando Alonso in 2015.

Hamilton was "brilliant" in the test, according to Rossi, who ran alongside the Briton on-track to help with his development and learning amid windy conditions.

Rossi is no stranger to Formula 1 cars, having previously completed a number of tests for Ferrari - and even came close to a race seat - but had not got behind the wheel of one for almost 10 years.

That all changed as the nine-time motorcycle world champion sampled Hamilton's championship-winning Mercedes W08 car from 2017, emblazoned with his famous #46 and 'The Doctor' sticker.

The pair then ran side-by-side on-track with Hamilton on the Yamaha MotoGP bike and Rossi in the Mercedes, marking a memorable end to a memorable day for two of motorsport's all-time greats.

You can watch highlights of their test in Valencia above.