Geraint Thomas will venture into "uncharted territory" when he leads Team Sky in a Grand Tour for the first time at the Giro d'Italia.
Thomas will share the leadership with Mikel Landa, having previously played a supporting role for his team-mates.
The 100th edition of the Giro, one of cycling's three Grand Tours - alongside the Tour de France and Vuelta a Espana - starts in Sardinia on Friday.
"It's one of the biggest challenges of my career," said Briton Thomas, 30.
"I've got a massive few weeks in front of me. I'm just looking forward to racing now. It feels like we've been talking about it forever.
"It's uncharted territory really. I've always been helping other guys so if I do blow up now it doesn't really matter. Hopefully it all goes well."
This year's Giro will comprise a gruelling, 21-stage route, starting in Alghero, Sardinia on Friday and ending in Milan on Sunday, 28 May.
It will be Welshman Thomas' third appearance at the Giro and his 11th Grand Tour start, though his previous outings have been as a support rider for the likes of British three-time Tour de France winner Chris Froome.
Thomas has shone in his role as 'super domestique' in cycling's showpiece events, while he has impressed as a leader in other races, winning the Tour of the Alps in April and Paris-Nice last year.
"Preparations have gone really well. I've got three wins this year which is certainly nice," the Cardiff-born rider told BBC Wales Sport.
"Being a support rider and a leader are two totally different things. I'm just relishing that opportunity and trying to make the most of it.
"It's been a long build-up and something I've been thinking about for a long time, so it will be good to get racing."
If he is to claim the winner's Maglia Rosa (pink jersey) in Italy, Thomas must overcome some formidable competition.
The favourite is Nairo Quintana, who won convincingly when he last appeared at the Giro in 2014.
A former Vuelta champion and runner-up at the Tour de France, the 27-year-old Colombian is a renowned climber who is expected to be well suited to a demanding Giro route.
However, the Movistar rider might be mindful of over-exerting himself as he keeps one eye on preparations for the Tour, which starts in July.
Other leading candidates include defending champion Vincenzo Nibali, one of only six cyclists to have won all three of the Grand Tours.
The 32-year-old Italian, nicknamed 'The Shark', won in dramatic circumstances last year as he capitalised on Dutchman Steven Kruijswijk's late crash to clinch his third Giro title.
"Nibali and Quintana have won this race before, they've got all that experience and, for sure, they're the favourites," said Thomas.
"Myself and Landa, we have a chance - but we're not at that level, I don't think."
Sharing the lead
Cycling teams tend to choose one rider to spearhead their Grand Tour campaigns, but Thomas will share his new role with Spaniard Landa.
The 27-year-old finished third at the Giro in 2015 while riding for Astana and Thomas believes their styles will be well suited to each other.
"He's obviously a great climber. He's been third in this race before, he's got the experience, he's a great athlete and he'll certainly give us another card to play," Thomas added.
"We can ride off each other. We get on well and I think it can work well. As we get into that last week there will certainly be gaps and one will be ahead of the other.
"Depending on how we're both feeling, I'd happily help him and vice versa. We'll see how it goes."
'No point putting extra stress on it'
Thomas has endured a difficult build-up to the Giro, following the death of his aunt Christine after a battle with cancer last week.
The double Olympic team pursuit champion was also shocked by the death of Italian cyclist Michele Scarponi in April, after the 37-year-old was involved in a collision with a van during a training ride.
Scarponi, a former Giro champion, had finished fourth at the Tour of the Alps, which Thomas won earlier that month.
Asked if his result at the Giro could define his career as a road cyclist, Thomas played down its significance given recent events.
"I don't think it would be a step backwards whatever happens. It's going to be a good challenge and, if it doesn't work out, then it doesn't work out," he said.
"What we've seen lately - what happened with Scarponi and I lost my auntie last week - it puts everything into perspective.
"It's a bike race, there's no point putting extra stress on it. At the end of the day, it's not the end of the world. It's just a great opportunity."