Alun Wyn Jones signs for Toulon as 'World Cup joker' - but what does it mean?

Ex-Wales and British and Irish lions captain Alun Wyn Jones has been confirmed as a 'medical joker' for a French rugby side.

Toulon announced on Friday he will join them during the World Cup campaign after Jones announced his retirement in May.

He is the most capped rugby player in the world after making his debut for the Ospreys in 2005, racking up 158 caps for Wales and 12 Tests for the Lions.

The Ospreys were among those to congratulate him on the announcement saying on Twitter, "Good luck to @AlunWynJones and his family at @RCTofficiel a true @ospreys great."

In a statement, Toulon director of rugby Pierre Mignoni said: "We are delighted and honored to welcome a legendary player like Alun Wyn Jones to Toulon. His career demonstrates the immense talent of this player.

"His experience, his mental and physical strength as well as his leadership will bring to the locker room and to his teammates."

But the word 'joker' in rugby terms might be unfamiliar to some, so what does it mean?

The signing of a medical joker is a club's way of ensuring they have enough cover and players to call upon when there is an injury in the squad.

It is a term more commonly used in France.

The player often takes up a short term contract and this case, Jones will be providing cover for teammates who are at the World Cup in September and with the Top 14 season kicking off next month.