What is it?
It's the semi-final of the William Hill Scottish Cup and will determine which of the Old Firm will play the winner of the match between holders Hibernian and Aberdeen in the final at Hampden Park on Saturday, May 27. Celtic have not won the Cup since 2013 while Rangers, runners-up in 2016, last won it in 2009.
Celtic have already tied up their sixth successive title, won the League Cup and are unbeaten in domestic competition this season. Rangers' mission is to trip their Treble chances at the penultimate hurdle, as they did with their Double opportunity last season in the Cup semi-final.
When is it?
Inscribe Sunday, April 23 in your diary and you can eradicate all doubt and uncertainty from your mind.
What time is kick-off?
The referee will be poised to give a blast of his Acme Thunderer at 12 noon sharp to commence proceedings at Hampden Park.
What TV channel is it on?
Sky Sports 2HD and Sky Sports 2 will be broadcasting the match, with the programme beginning at 11.30 to soak up all the atmosphere. Neil McCann, a mainstay on Sky's Scottish football coverage over the years, may be absent now he has taken over as interim Dundee manager until the end of the season.
Fear not if you are not a Sky subscriber, you can join us here for minute-by-minute coverage helmed by Alan Tyers.
What is the team news?
Celtic's captain Scott Brown was sent off towards the end of last weekend's 2-2 draw with Ross County but the club immediately appealed the red card after the match and because the hearing takes place next week he is eligible to play at Hampden on Sunday.
Mikael Lustig and Dedryck Boyata missed the trip to the Highlands to play Ross County but are expected to return to the defence at the weekend.
Rangers are unbeaten since Pedro Caixinha took charge on March 13, winning three and drawing two of their matches. His most notable innovation has been the introduction of 20-year-old central defender David Bates and the 18-year-old left-back Myles Beerman for the past three games and both have performed with admirable composure. Caixinha hopes Clint Hill, who scored the equaliser in the last Old Firm match, will be fit for Sunday after missing the draw with Kilmarnock and victories over Aberdeen and Partick Thistle.
Hill, 38, pulled his hamstring during the draw with Motherwell and had to go off at half-time and though Caixinha thinks it will be touch and go for the veteran, he has no qualms about playing the youngsters, as he told the club's website:
"So far they have done very well, the team has done very well and helped them also to be on the same wavelength, so if they need to play or if they need to start that game I have no problems with that," he said. "If Clint can be with us, perfect, he’s a valuable and experienced player, he’s a warrior and someone who is always looking to help us and always demanding from team-mates.
“We like those sort of players and if he can be with us, perfect. If not, others will do their jobs in the same way because this is a collective work, this is teamwork and we need to think and keep thinking the same way."
What are they saying?
Dedrick Boyata, the Celtic defender who played in the losing semi-final last year, says Sunday emphatically is not about redemption:
”It’s easy to compare to last year due to the fact we lost the game at the same stage. But last season was last season and this is a new season, " he told Celtic View.
"It’s a new game for us and we will gear up for it like we did the previous four games against them this season and we will be prepare well.
“All the players are ready to give 100 per cent for the badge, just like we have in the other derby games. We know the importance of the game, there is no doubt about, and we will give everything to make everyone proud of us.”
Caixinha was in the stands for the 1-1 draw last month but is looking forward to his first Old Firm match in charge: “I’ve had them in Mexico, Portugal, Greece, Romania and with national teams. I like those type of matches and I like matches which are more about the strategical side of the game, and I love that.
"I think I am going to be a guy who will enjoy the game and seeing if things are going to go the way we have worked with them along the week. It is going to be a fantastic environment and a fantastic football match. We need to be prepared to play it and win it.”
What are the odds?
What's our prediction?
A draw like last year but this time Celtic will prevail on penalties.