The ultimate challenge of learning a new sport.
Since the inclusion of Rugby Sevens at the Olympics, rugby's stars have been seeking new challenges and opportunities as they strive for gold in Rio.
Not many players have been able to achieve stellar careers in both formats, with union and sevens needing different skills and approaches.
It will be a difficult task for the likes of Quade Cooper and Sonny Bill Williams, who don't boast sevens backgrounds, but it is a challenge that both - as well as many other union stars - are willing to accept with the Olympics beckoning.
Here at Inside Sport we've compiled a gallery of some of the best players from this part of the world who have enjoyed very successful careers in both rugby union and rugby sevens ... or are aiming to join the elite list at least.