Keith Earls: I feel like this is the start of my career again
There's something completely genuine about Keith Earls. Whether it's the way he continues to bounce back from setback after setback or how he conducts himself off the pitch, it's difficult not to be enamoured by his sheer desire to succeed.
Earls' career has been hampered by injuries and while he has always managed to claw himself back from the depths, there did come a time when he wondered was it all worth it.
Having had his 2013 season curtailed by a shoulder injury suffered against Wales in the Six Nations, Earls suffered a fresh knee injury just one month into the new campaign.
It was a luckless run, and looking back on it now, the mental anguish is still evident.
"I was due to play against Glasgow a couple of years ago and I twanged my knee," he recalls. "I was just getting back - I'd played two games before it.
"Rob Penney gave me a shot at centre and I'd been training there. The Thursday before I flew out, I got injured and the scan showed a tear in my patella tendon.
"I rehabbed that for a couple of weeks and came back but it didn't work out. During the summer holidays it wasn't feeling any better. I didn't know at the time that tendons like to be worked.
"I thought rest was good for it. It was actually making it worse. When I came back for pre-season I was told I had to have an operation.
"None of my injuries were as serious as Lukey's (Fitzgerald) but at times, I was thinking, is this worth it?"
Earls was forced to reshape his mindset and in particular, how he set goals for himself.
It wasn't an easy process but it was one that allowed him to take stock of how he was going to fulfil the promise he showed as a blistering 19-year old who broke onto the scene.
"Some of my interviews have been boring, I haven't really looked past a week because when I had been, I was getting injured," he admits.
"I had been trying to rush things to get back for certain games but it's all about getting my head right mentally and my body physically.
"It's happened really fast again, it's nearly like the start of my career again. I've worked really hard.
"I sat down before I came back training and set myself the goal of making the 31-man squad and then set myself another goal of making the 23-man match-day squad.
"I'm delighted, I'm fit and I'm healthy. I'm grateful that I'm playing."
Aside from a brief scare in the second warm-up against Wales when Earls was stretchered off with concussion, his sights are now firmly set on the coming weeks.
Tomorrow at the Millennium Stadium, Irish supporters will finally get to see two of the country's most naturally gifted players line out alongside each other, on the world stage.
Seven years ago, on a miserable night in Thomond Park, Earls' international journey began with a try with his first touch on his debut against Canada, and it was Fitzgerald's perfectly weighted pass that put him over in the corner.
The Leinster flyer has endured a similarly brutal time with injuries; the pair's relationship dates back to when they were both lighting up schools rugby.
"I met Luke in Clongowes - we had Irish schools camps there. I was aware of him - sure, he was phenomenal in school," Earls smiles.
"We played Irish Schools together. We're from two different parts of the country, two different upbringings even but we clicked straight away of the field.
"It's been frustrating we didn't (play together) really. He's a fella I enjoy playing with because he's a dangerous player."
When Earls came off second best in a collision with George North three weeks ago, many feared the worst, again. But as he explains:
"It was my own fault, just getting my head, well, it was an instinct, when George North is running at you, you tend to put your head down to knock him.
"It was actually one of the first questions I asked the doctor, 'did I knock him?' That was the main thing for me but, yeah, I came around fully."
It's that attitude that makes Earls so endearing, and now that he is back on the world stage, he is determined to make the most of it.
"It (World Cup) is the biggest stage in the world, it's the highest stage you can play at in our sport so I'm delighted," he says.
"I've made a lot of sacrifices to get here and I'm sure my fiancée and my family are delighted it's paid off because they've had to put up with me training a lot."
It's been a long road back to the top but it's one that has made Earls even stronger.