Andy Farrell has branded following Joe Schmidt as Ireland head coach the biggest challenge of his career.
Former dual-code England international Farrell will step up from assistant to head coach when current boss Schmidt steps down after the autumn's World Cup in Japan.
The 43-year-old has worked under Schmidt since 2016 amid Ireland's rise to second in the world, following four years as England defence coach.
Farrell confirmed Johnny Sexton will be fit for Ireland's Guinness Six Nations trip to Italy on Sunday, February 24, with Iain Henderson also in the running to feature – before briefly turning attention to life after the 2019 World Cup.
Asked if replacing Schmidt will be his biggest coaching challenge yet, Farrell replied: "Yes, 100 per cent. It's something I've been working towards, something I'm up for and excited about at the same time.
"I'm proud and privileged to be asked to take over after such a brilliant coach like Joe (Schmidt).
"Fortunately enough as well I get a bit of time to keep on learning in the meantime.
"It's a massive honour to be given the opportunity, because it's a privilege to be involved with the group of people we've got, the players and the staff.
"I feel where we're going in the future is a bright place as well."
Schmidt has led Ireland to one Grand Slam, three Six Nations titles, Ireland's maiden two victories over back-to-back world champions New Zealand and from eighth to second in the World Rugby rankings.
Ireland confirmed Farrell as Schmidt's replacement when their current boss revealed in November that he would step down at the end of 2019.
Farrell enjoyed a stellar playing career in both league and union, before making his coaching name at Saracens.
The British and Irish Lions coach lost his England job after the 2015 World Cup, when Stuart Lancaster's side became the competition's first host nation to be eliminated at the group stages.
Farrell has flourished under Schmidt's tutelage however, and feels he has progressed enormously in the Ireland set-up.
Asked if he had had any second thoughts over replacing Schmidt, Farrell replied: "Absolutely no doubts whatsoever, it was a very easy decision.
"Of course I have become a better coach under Joe, 100 per cent.
"You're learning all the time, aren't you? No matter who you're working with.
"What you get when you're in our environment is you get to share ideas and we tend to give quite a lot of feedback to each other
"You're learning constantly and it shapes the way you think and learn on the run."
Farrell's former England boss Lancaster has been mooted as a candidate to leave Leinster and join Ireland's backroom staff once Schmidt departs.
But Farrell kept his cards close to his chest when quizzed on the chance of linking back up with former Leeds coach Lancaster.
"There's planning that has to go on behind the scenes," said Farrell.
"Honestly I'm unbelievably conscious of making sure nothing gets in the way of the day job.
"Things are petering away, but there's not too much wrong with the Irish set-up at this moment in time.
"Continuity is a good thing for us, because what we do is working."
Ireland will move on to face Italy in Rome next Sunday, keen to build on their 22-13 win over Scotland in Edinburgh.
Confirming Sexton's fitness after a head injury scare, Farrell hailed Ulster lock Henderson's return ahead of schedule from a finger injury.
"Johnny is fine, he trained fully and he will be ready to go," said Farrell.
"He is fine, he's had no symptoms at all, no complaints throughout the week."
On Henderson, Farrell added: "It's great to be getting players back; it's nice to get a boost throughout the Six Nations.
"For fresh guys to come back in with fresh spirits will hopefully give everyone a boost."