The Wessex League premier division Royals have already beaten Mangotsfield United and Bideford.
Both of those teams play in the south & west division but this time the Royals have premier division opposition.
Manager Graham Rix is looking forward to another great occasion after his side also progressed in the FA Vase last weekend.
He said: ‘There is no doubt this is the biggest game in the club’s history and the toughest.
‘For us it will be a case of sticking to our game plan and showing the same levels of concentration that have got us here.
‘It is the FA Cup and you never know.’
In the Wessex League premier division, Moneyfields have striker Steve Hutchings back as they defend their unbeaten record against Amesbury Town at Dover Road tomorrow (3pm).
Hutchings has missed the last few games through illness and suspension.
Manager Dave Carter is hoping the return of his star striker will be a big boost.
He said: ‘We have kept winning games despite missing a load of chances.
‘When we have had chances to put teams away we have not done so.
‘We want to keep up the pressure on leaders Blackfield & Langley.’
Curtis De Costa is out after dislocating his shoulder.
Lewis Fennemore and Dan Gauntlett are injury doubts while Nathan Paxton is away.
Horndean visit Team Solent tomorrow (3pm).
The two teams also met on Monday in the league cup with Team Solent winning 3-1.
Deans boss Michael Birmingham rested seven senior players for that match.
He said: ‘To be fair the lads that came in did well.
‘Team Solent have got all their students back and they are powerful, strong and quick all over the park.
‘We were excellent in the FA Vase at New Milton and the football we played in the first half was the best since I took over.
‘Our movement and rotation was excellent.’
Fareham Town travel to Fawley aiming to stop a run of four league defeats (3pm).
The Reds will be looking to bounce back from their Hampshire Senior Cup exit at the hands of Eversely & California in midweek.
In division one Baffins Milton Rovers go to Laverstock & Ford, while United Services visit Downton.