England centre Joel Tomkins insists playing at Twickenham on Saturday will justify his decision to switch codes - even if the 2015 World Cup remains his true goal.
Dual code star Tomkins will make his debut in the opening QBE International against Australia two years after swapping Wigan Warriors for Saracens.
England head coach Stuart Lancaster has been impressed by the big-game temperament shown by Tomkins, but the 26-year-old admits the Wallabies at Twickenham will be his greatest challenge yet.
"This was always a massive goal for me, probably the biggest goal and the biggest factor in coming over to rugby union," Tomkins said.
"I wanted to play international rugby and I wanted to play at Twickenham, in front of 80,000.
"Then, ultimately, I want to play in the World Cup. The World Cup is definitely a big goal of mine.
"I've played in a couple of finals for Wigan and played international rugby league. I can draw on those experiences.
"Saturday's going to be one of the biggest, if not the biggest, crowd I've ever played in front of, but I see it as exciting.
"This is the reason I came over to rugby union. I want to play in these games."
Tomkins has forged a similar path to Chris Ashton, who left Wigan for Northampton in 2007 and has since established himself as England's first-choice wing.
It was the influence of his friend that convinced Tomkins to join Saracens when he was approached in 2011.
"As a kid growing up in Wigan there's no other sport other than rugby league. You just grow up with a certain passion to play the sport," Tomkins said.
"On Friday nights when Wigan are at home the whole town stops and everyone goes to the game.
"As kids that's what you want to do, there are no other distractions really. No-one wants to be a footballer, everyone just wants to play rugby.
"Then, as you get a bit older, your skills become a bit more transferable to rugby union and there are definitely other opportunities in union - the international game, the European game.
"Chris moving over to union gave me a bigger interest in it and I've followed it since then really.
"It was quite a last-minute thing, at the end of the 2011 season."
While Tomkins is making his debut at Twickenham in front of his parents, his brother Sam will be playing for England against Ireland in the rugby league World Cup.
Sam recently agreed a high-profile move to the New Zealand Warriors and Joel refused to speculate on whether he might play union later in his career.
"Sam's always been a bit special, even as a kid. He's always been the smallest bloke on the pitch, who could do something special," he said.
"Everyone has always known that he had the potential to go on and do special things, which he has done.
"I definitely hope for the next few years everybody can just let him be in New Zealand to do the best he can because he has got a massive challenge ahead of him."