The two sides clash in the heat of the east Midlands derby on Friday night at Welford Road.
But, collaborating on behalf of Land Rover, the Premiership stars put rivalries aside to help pass on some of their knowledge to Harborough's stars of the future.
George Ford, Jonny May, and Ellis Genge combined with Dan Biggar, Piers Francis, and Cobus Reinach to give the youngsters a night they will not forget.
Internationals Biggar and Ford provided a place kicking masterclass, while Genge shared tips on the dark arts of scrummaging.
May, Reinach, and Francis assisted with the backs to develop one-on-one footwork and attacking drills.
With just six points separating sixth and 10th in the Gallagher Premiership, it has been one of the closest domestic seasons on record.
A victory for either side will go a long way in securing a top-six finish meaning Friday’s derby is expected to be another fierce encounter.