1) Sonny Bill Williams
The all-conquering Williams was bought out of his contract with NRL club Canterbury Bulldogs in the middle of the 2008 season, taking up a two-year deal with French Union side Toulon. He then went back to New Zealand to join the Crusaders and played in 19 Tests for the All Blacks including games in their successful 2011 World Cup side before a dominant 2012 season as an prolific offloader, helping bring up a Super Rugby title for the Chiefs.
He made the lucrative switch to Japanese rugby in 2012 before a hugely successful stint back in League with Sydney Roosters, where he won the 2013 NRL title before playing in the 2013 Rugby League World Cup where New Zealand reached the final.
Arguably the only player who is seemingly able to switch between the two sports at will, he returned to Union this year in preparation for the Rugby Union World Cup, where he was played a form part as New Zealand look to rumbled towards retaining their title.
Just for good measure, he is also New Zealand’s heavyweight boxing champion.