This will be the home side's third pre-season friendly, while the visitors are gearing up for their sixth of seven pre-season matches.
Match preview
Wycombe are preparing for another season in England's third tier league having already spent three seasons there and finishing 10th last term.
Since being relegated from the Championship in 2020-21, the Chairboys have reached the play-offs just once, losing to Sunderland in the 2021-22 final.
Wycombe were close to achieving some success last season, but they fell short in last season's EFL Trophy final, suffering a 2-1 defeat to Peterborough United.
The club has recently undergone a change of ownership, with the new owners aiming for promotion to League One at the end of the 2024-25 campaign.
However, pre-season has not started ideally, with a 1-0 loss to Notts County followed by a 2-2 draw with Colchester United in a behind-closed-doors practice match.
Watford have also had a mixed pre-season under new manager Tom Cleverley as they look to return to the Premier League after two seasons in England's second division.
The Hornets have lost to Reading and Gillingham, but have beaten Boreham Wood and Hibernian, as well as drawing with Stevenage in the five friendlies they have played.
Cleverley was initially appointed as interim manager before being given the job on a permanent basis, but the club finished in the bottom half of the Championship last season.
Watford will be hoping to build on their recent win over Hibernian as they prepare for the opening league game against Millwall on August 10.
Wycombe Wanderers friendly form:
D
Wycombe Wanderers form (all competitions):
W
W
W
D
W
D
Watford friendly form:
L
W
Watford form (all competitions):
L
L
W
D
L
W
Team News
Matt Bloomfield has fielded different XIs in the four halves Wycombe have played so far across both friendlies, and he is expected to do the same on Tuesday.
Richard Kone scored the second goal after coming on in the draw with Colchester, and this could earn the forward a place in the starting XI.
Watford's win over Hibernian featured a mix of first-team and academy players, with Rocco Vata producing an impressive performance as he got on the scoresheet.
Michael Adu-Poku also put up a solid performance after coming on, while Tom Ince continued his good pre-season.
Wycombe Wanderers possible starting lineup:
Bishop; Grimmer, Harvie, Low, Hartridge; Bakinson, Ward, Butcher, McCleary; Kone, Udoh.
Watford possible starting lineup:
Bond; Pollock, Sierralta, Porteous, Ngakia; Louza, Ramirez-Espain, Morris, Vata, Ince; Baah