Billy Vunipola (England) 
Position: No8

Tests: 5
The big, bruising Saracens back-row forward has given the Red Rose a new dynamism at the base of the scrum since coming into the side in Argentina. Made the second-most metres with ball in hand against the All Blacks, while putting in a performance that highlighted his class.

Maxime Machenaud (France)
Position: Scrum-half
Tests: 11
Has, rather surprisingly, been confined to the bench for today’s game against England but is sure to have an influence when he steps into the action. Has impressed during a difficult season for Racing Metro and provides a kicking option too, a handy attribute late in games.

Jonny Sexton (Ireland) 
Position: Fly-half 
Tests: 38 
Sexton has endured an up and down debut season in France, admitting this week that he had questioned his decision to join Racing from Leinster at times. Remains pivotal to Irish hopes of Six Nations success, though, with his metronomic kicking but he does has a point to prove.

Sergio Parisse (Italy)
Position: No8
Tests: 101 
Scored a try in the historic victory over Italy in Rome last season and was instrumental as Italy beat Ireland there a month later. Is the wrong side of 30 now but the Argentina-born No8 is still regarded as one of the best back-row forwards in the world. And experience always counts. 

Johnnie Beattie (Scotland)
Position: Back row
Tests: 26
Another Six Nations star plying his trade in France, the Montpellier forward has had to endure an injury-interrupted international career making only 12 appearances in the Six Nations since his debut in 2007. Will be hoping to help Scotland pick up a few scalps this year.

Justin Tipuric (Wales)
Position: Flanker
Tests: 19
The Ospreys forward has emerged as his country’s in-form flanker over the past year, putting both captain Sam Warburton and Dan Lydiate’s places in the team under pressure. Earned a start for the opener against Italy and will be looking to showcase his destructive skills.