Star Welsh winger George North, in his rugby comeback in Saturday's Test against Ireland, will break a world record held by Australian Joe Roff.
At 23 years and 138 days, the Northampton flyer will become the youngest player in rugby Test history to reach 50 caps for his country.
North made his Wales debut against South Africa in November 2010, scoring two tries.
He has 22 tries for Wales and stands fourth on his country's all-time list behind Shane Williams, Gareth Thomas and Ieuan Evans.
Roff was was 24 years and 40 days when he clocked up a half-century for Australia against South Africa in 1999.
The top six is completed by French halfback Morgan Parra (24 years and 114 days), Italy No.8 Sergio Parisse (24 years and 151 days), England five-eighth Jonny Wilkinson (24 years and 168 days) and New Zealand fullback Christian Cullen (24 years and 280 days).
North returns to action on Saturday for his first appearance since late March. He suffered three concussions last season, but is fully fit and lines up at the Aviva Stadium in Wales' second-last World Cup warm-up Test.
** Statistics refer only to matches for the player's own country and do not include appearances for the British and Irish Lions.
Share
