The unlikely pair face off for a place in the showpiece final, with Manchester City and Brighton & Hove Albion contesting the other final-four affair.
Watford's run to the semis has not been as daunting as Wolves', having had to battle past non-league Woking, Championship side Queens Park Rangers, and bottom-half Premier League teams Newcastle United and Crystal Palace.
That ultimately counts for nothing, though, as the teams are on equal footing at the national stadium this weekend. There is also very little between them in the Premier League, separated by just one place, one point and one goal.
Wolves have enjoyed the more impressive campaign by virtue of this being their first season back in the big time, but it has also been a hugely encouraging eight months for Watford under impressive boss Javi Gracia.
Gracia is the ninth Watford boss to be appointed during the ownership of the Pozzo family since 2012, becoming the first to sign a contract extension with the club in that time when putting pen to paper on a long-term deal in November.
After years of gambling, which did bring with it some prolonged success, it should be said, the Hornets have finally found the right manager for them and they are on course for a historic season - regardless of Sunday's result.
As well as competing for a place in the FA Cup final for just a second time, having finished runners-up to Everton in 1983-84, Watford are already assured of their highest-ever points tally in the Premier League era.
Their midweek win over Fulham, thrashing their opponents 4-1 after a half-time shuffle, leaves them eighth in the Premier League and a point behind Wolves in the race for European football.
Earning a Europa League spot can also be secured through winning the FA Cup, of course, and Gracia can move a step closer to achieving that with victory this weekend.
The problem for Watford, though, is that they have won just one of their six games in all competitions at Wembley Stadium (2-0 vs. Bolton Wanderers in May 1999), losing each of their last four at the ground. End that hoodoo and Gracia will be on course to writing his name in club folklore.
Recent form in FA Cup: WWWW
Recent form (all competitions): LWLWLW
In stark contrast to their semi-final opponents, Wolves have won their last six games at Wembley - only Arsenal and Tottenham Hotspur (both with seven) have won more consecutively at the ground.
Wolves have earned a reputation for giving the top six a bloodied nose this term, with Tuesday's 2-1 comeback win against Manchester United - a little over two weeks on from beating the Red Devils in the FA Cup quarters - making it 13 points collected from a possible 30 in such fixtures.
Nuno Espirito Santo's men have taken more points from the established elite than any top outside the top group, in fact, though on the flip side they have all too often fallen short against the so-called lesser sides.
A case in point was last weekend's 2-0 loss at Burnley, coming a month on from their defeat at Huddersfield - having also lost the reverse match - and defeats against the likes of Cardiff City, Brighton and Crystal Palace.
Perhaps more relevant to this weekend's meeting, Wanderers suffered a 2-0 loss to Watford at Molineux a little over five months ago in their only previous league meeting to date this term.
The reverse fixture, incidentally, is scheduled for April 27 - could that be a playoff fixture of sorts to see which of these sides, if any, plays European football next season?
All attention for now is on the FA Cup, though, and Wolves certainly boast more pedigree in the competition than Watford. The Midlanders are playing in their 15th semi-final - albeit a first since 1998 - and they lifted the trophy in 1960 under Stan Cullis.
That is in comparison to Watford's seven previous FA Cup semis, only one of which they have won to give them the joint-lowest progression rate alongside Fulham (1/6 – 17%).
Neither of these sides would have expected to be in with a shot of cup glory this term. In a battle on two fronts, Sunday's match will have the feel of a final in many ways to supporters of both clubs.
Recent form in FA Cup: WDWWW
Recent form (all competitions): LWDWLW
Pereyra has been key to the Hornets' success this term, starting 29 of their 32 Premier League matches, and Gracia will be desperate to get the Argentinian attacker back to full fitness.
Wolves have no fresh injury concerns for Sunday's match, meanwhile, maintaining their reputation as the fittest side in the division.
Watford possible starting lineup:
Gomes; Femenia, Kabasele, Cathcart, Holebas; Pereyra, Doucoure, Capoue, Hughes; Deulofeu, Deeney
Wolverhampton Wanderers possible starting lineup:
Ruddy; Bennett, Coady, Boly; Doherty, Dendoncker, Neves, Moutinho, Jonny; Jimenez, Jota
Head To Head
Of their previous seven FA Cup meetings, Watford have won only one - a 3-0 victory in the fifth round just under 40 years ago.
Wolves' second-biggest ever win in this competition came against this weekend's opponents back in January 1912, thrashing the then non-league outfit 10-0 in a first-round replay.
The Hornets have only lost one of their last five matches against Wolves in all competitions, though - a 1-0 loss at Vicarage Road in December 2014 when the sides were battling it out in the Championship.
We say: Watford 1-2 Wolverhampton Wanderers
Would Wolves have preferred to face Man City this weekend, having already knocked out Liverpool and Man United, as well as overcoming the big boys in the Premier League? Probably not, but this will be a different type of test for Nuno's men, who we are still backing to edge through for a place in the final.