Rory McIlroy has been paired alongside Charl Schwartzel and world number one Dustin Johnson for the first two days of the Open Championship.
McIlroy has had a less-than-ideal build-up to the Merseyside major, missing the cut in his last two events.
The trio will take to the first tee just before 2.50pm on Thursday.
Darren Clarke is first of the Irish out at 9.25am, he is alongside Gary Woodland and amateur Harry Ellis.
Padraig Harrington tees off 10 minutes later with Thomas Pieters and Pat Perez.
It is the first time Harrington will play a tournament at Royal Birkdale since winning the Open there in 2008.
Then at 10.20am Shane Lowry gets his first round underway alongside Brandt Snedeker and JB Holmes.
They are the only Irish players to feature at this week's major as Graeme McDowell and Paul Dunne just missed out on the final qualifications spots up for grabs at last weekend's Scottish Open.
Somes ot the stand-out groups sees Masters champion Sergio Garcia play with 2015 Open winner Zach Johnson and former world number one Jason Day.
Elsewhere, reigning champion Henrik Stenson is paired with Si-Woo Kim and former Masters champion Jordan Spieth.
Stenson was pessimistic about his chances despite a closing 68 in the Scottish Open on Sunday, after which he was asked if he could emulate Harrington in winning back-to-back Open titles at Birkdale.
"I think we're hoping for a lot in terms of what we saw this week," the 41-year-old said. "We certainly need to step that up quite a lot if we want to have anything to do with it next week.
"There's always a chance and I'm going to enjoy the week. You never know, it might be the only time we're defending champion at the Open Championship so I might as well enjoy it."
You can see the tee-off times and pairings for the first two days of the Open Championship here.