As Gavin Henson gets set for his rugby league debut at the age of 39 this weekend, we look at three union stars who also made the code switch later in their careers, but it didn't quite work out...
Luther Burrell
The most recent example of a union star heading for league saw Burrell, a 15-cap England centre, swap Northampton Saints for Warrington Wolves in 2019.
The now 33 year old had played league as a teenager and was keen to test himself in Super League, but things didn't go as he'd planned.
Thanks started positively as he came off the bench and helped the Wolves to a 36-6 win at London Broncos in July.
He started two games thereafter; a 30-12 loss at home to eventual Grand Final winners St Helens and a 22-6 loss to Salford Red Devils on the road without troubling the scoresheet.
Warrington won the Challenge Cup in 2019 but Burrell was only on the fringes of the first team.
He then started 2020 as a regular fixture coming off the bench and had racked up five appearances by February, but Warrington were faltering with only two wins before the national Coronavirus lockdown took hold.
Burrell was unable to get the breakthrough he wanted after the season restarted, so returned to union with Newcastle Falcons having made a total of eight Super League appearances, including two starts and no tries.
The Huddersfield-born back has no hard feelings after his league spell, however, telling The Guardian: "I come back to rugby union as a better person and player, despite it not working out in league.
"I’ve got some Super League games under my belt, I’ve experienced another sport and I wouldn’t be where I am now without going to Warrington. Did it work out? No, clearly, but it’s all added to my rugby CV, if you like.”
Andy Powell
After an eventful union career which included time with nine different clubs, 23 Wales caps and an infamous golf buggy incident, Andy Powell arrived at Wigan Warriors in 2013 to much fanfare.
The union flanker was 32 years old at the time and his huge frame made him an ideal fit as a prop for the Warriors.
However the forward, who was part of the Lions squad in 2009, never truly adapted to his new surroundings, despite his experience of playing league growing up with Cardiff Demons and Halifax.
He made his debut in June that year, coming off the bench for the club in a surprise 18-4 loss against Castleford Tigers.
He was on the winning side - beating Bradford Bulls 26-20 - a week later, but was soon sent on loan to South Wales Scorpions to further his league experience.
The prop then failed to feature for the club until the penultimate game of the regular season - he came off the bench to score a try in a dramatic 34-33 loss against Hull FC.
Over the following two weeks, he would go on to start in a 20-6 loss to Leeds Rhinos, before he was hauled off after just nine minutes of a play-off match against Huddersfield.
Quizzed on his time as a league player during his Wigan stint he said: “The first few weeks I felt like going back to union because it was that hard.
“I didn’t want to get out of bed for a week because it was that bad - it was like being hit by a tram.
“In union, everything came naturally but here I have to think about everything and it’s taking time getting used to the different techniques.
“I’m the same weight but my body shape has changed. My fitness is getting there, but it’s the contact areas I have to work on.
"It could take me another two or three years but I will do it.”
He went on to play the closing minutes of that Huddersfield match, a hard-fought 22-8 win, however that proved to be his final act on a rugby league field as he swapped back to union with the Dragons, having made a total of six rugby league appearances, before retiring from the sport in 2016 after a battle with injury.
Gareth Thomas
One of the most iconic players of his era, Gareth Thomas swapped union for league at the age of 35 after an impressive career in union which saw him collect 100 Wales caps, scoring 50 tries, and captain the Lions in 2005.
Thomas made the high-profile move to Crusaders RL in March 2010 but was concussed just 22 seconds into his rugby league debut against Catalans Dragons. He eventually came off after half an hour as his side went on to win 14-6.
The Bridgend-born star featured at wing, centre and second row during his time as a league player, and did manage to make 13 appearances and score three tries in his first season in the sport.
A groin injury ended his club season in July, before he racked up an eye-catching four appearances and four tries for Wales in the 2010 European Cup.
Crusaders overcame the odds to reach the play-offs that year, but their fortunes would dip dramatically in 2011.
Thomas managed a further 18 appearances and four tries for the club before breaking his arm in July, but Crusaders' results were largely disappointing as they finished bottom of the Super League table and entered administration after financial difficulties.
The club announced their withdrawal from the league on July 26 and would go on to disband after the end of the 2011 season.
After 31 total appearances, 30 starts and seven tries, he announced his immediate retirement from the sport in October after failing to fully recover from injury.