The last time Chelsea and Leicester City met in the competition was in the Final in 2021, where Leicester prevailed and secured their first-ever FA Cup trophy.
Silverware was won thanks to a Youri Tielemans rocket, but also a crucial VAR decision against Ben Chilwell after his effort was disallowed for offside.
Since this meeting, Chelsea have changed their ownership and been under four different managers.
Meanwhile, Leicester have also had difficulties of their own; being relegated from the Premier League last season.
However, their Championship campaign indicates that they could cause eight-time FA Cup winners Chelsea some real problems.
Before the latest round of Championship action, the Foxes were level with Ipswich Town for the most goals in the league this season, with 74.
This is almost double Chelsea's tally who have only managed to net 47 times so far this season.
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Who will Chelsea have to pin down to numb Leicester's threat?
To no surprise, Jamie Vardy is Leicester's top scorer this season with 15 goals and is on course to be the club's top scorer for eight of the 12 seasons he has played there.
Yet, it isn't just the 37-year-old who has been putting up double digits for Maresca so far this season.
Kiernan Dewsbury-Hall and tricky winger Stephy Mavididi are just behind the English veteran, both on ten goals.
The three Englishmen have been the outstanding performers for the Foxes, but this isn't to say Maresca has a light squad as it is stacked with even more quality.
Patson Daka, Kelechi Iheanacho and Wilfred Ndidi are just a few of the names with top-flight experience, and all are capable of scoring.
This Leicester side may be the best the Championship has ever seen in terms of quality and depth, meaning Mauricio Pochetthino has a great task on his hands in his set-up.
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How can Pochettino break down Maresca's set-up?
Under Brendan Rodgers, Leicester operated in either a 4-1-4-1 or 4-2-3-1 formation.
This was to attempt to get the best out of an illustrious midfield that included the likes of Ndidi, Tielemans and James Maddison.
Since his arrival, Maresca has organised his side in a balanced 4-3-3 formation to step away from relying on a midfielder destroyer in the 'number 6' position.
By bringing Harry Winks into the fold, the 44-year-old has been able to implement a more possession based style.
During the season, Chelsea have looked strong when teams have played the possession game and could do the same again on Sunday.
They performed well against Manchester City in both league meetings by soaking up pressure and then being effective on the counter-attack.
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Who can Chelsea use to wound the Foxes on the counter-attack?
Pochettino has an abundance of attacking ammunition that he can use to hurt Leicester, and it showed in their midweek league victory over Newcastle United.
They have pace available through the likes of Raheem Sterling and Mykhailo Mudryk, who scored a fantastic solo goal against the Magpies.
Nicolas Jackson, who also scored on Monday, is another of their attackers who can cause issues on a fast break due to his speed, but also his ability to shrug off his opponents.
Another player who is more than capable of this is their catalyst, Cole Palmer.
The 21-year-old has recorded 19 goal involvements in 19 Premier League games this season, the most of any Chelsea player.
His technical ability is his outstanding talent, and it enables him to swiftly move away from defenders and create space.
During his time at Manchester City, Palmer won the FA Cup in their treble triumph and with his hot form, he could propel his side another step towards another cup final this season.
