McIlroy leads stellar field as golf's elite reunite at British Open
England's Matthew Jordan will hit the first tee shot at 0635 local time (0535GMT), at the Royal Liverpool club where he is a member, but McIlroy is the centre of attention as he returns to the course where he lifted the Claret Jug for the only time in 2014.
The Northern Irishman backed up that victory by winning the PGA Championship the following month, but has been stuck on four major titles ever since.
McIlroy came agonisingly close both at last year's Open Championship at St Andrews and last month when he missed out at the US Open by one shot to Wyndham Clark.
However, doubts over the 34-year-old's ability to handle the pressure coming down the stretch on Sunday were dispelled last weekend as a birdie-birdie finish in blustery conditions brought McIlroy the Scottish Open for the first time.
"I could not ask for better preparation," said McIlroy. "The way I played the last two holes (in Scotland) was an amazing finish and a perfect way to come into this week.
"I've had a great nine years and won a lot of tournaments but the big four have eluded me. Hopefully this week that's something I can change."
McIlroy is among the late starters on Thursday as he tees off alongside Masters champion Jon Rahm and former world number one Justin Rose at 1359GMT.
Scheffler not satisfied
Scheffler has also had a stellar year on the PGA Tour, but is yet to add to his sole major win at the 2022 Masters.
The American has not finished lower that 12th in 16 tournaments this year and was in the top three at both the PGA Championship and US Open.
"It's really fun winning. It's not as fun finishing third," said Scheffler. "Golf is one of those games where I don't think you ever really achieve that satisfaction. I think you're always asking for more."
The final major of the year comes just weeks after a shock announcement that the PGA and DP World Tours plan to merge with the breakaway LIV Golf series.
A "framework agreement" between the parties has left the players on both sides of the divide short on detail on what the future of the sport will look like.
"I don't even think the guys that are trying to sort it out really know what this outcome is going to be like," said defending champion Cameron Smith, who defected to LIV shortly after winning his first major 12 months ago.
Without a concrete agreement, all the world's best would not be reunited in battle again until the Masters next April.
The form of Smith and Brooks Koepka has so far dismissed suggestions that the stars who took huge signing bonuses to join LIV would see their competitive senses dulled.
Koepka claimed his fifth major at the PGA Championship, just a month after finishing second at the Masters.
Those results have propelled Koepka into contention for a place at September's Ryder Cup despite only being eligible to pick up points at the majors.
Another strong showing will make him hard to ignore and he is not the only one hoping to catch US captain Zack Johnson's eye.
"I would love a big week. Obviously the goal is to win. That's what it is every week," said 2021 Open champion Collin Morikawa.
"Ryder Cup is obviously a huge goal of mine and has been for the past two years, especially turning into the beginning of this year, and it still is."