The club narrowly missed out on a trip to Wembley after being held by a late goal against Manchester United at Old Trafford before losing 2-1 in the replay at Upton Park earlier this month.
So what changes does Bilic need to make to the side that started against the Hornets to bring all three points back to London?
Collins in for Reid
James Collins has been West Ham's best defender this season and his injury seriously derailed the club's progress in both the FA Cup and league.
In the 11 games he and Angelo Ogbonna have played together this season the Hammers have conceded just eight goals compared to 30 conceded by Winston Reid and Ogbonna in 19 games together.
Reid has looked off the pace since returning from injury and has been at fault for a number of goals recently as well as picking up early bookings which has left him walking a tightrope for the rest of the games.
Byram in for Sakho
Diafra Sakho returned to the West Ham team and produced a solid display up front alongside Andy Carroll against Watford.
The Hammers will not be so brazen as to play two up front away from home given the attacking mindset of their midfield stars Payet and Lanzini.
Sam Byram has barely featured due to niggles and being cup tied since signing from Leeds United but has impressed when he has.
He should come in for Sakho to take the place of the brilliant Michail Antonio, who has been playing - fantastically - out of position at right back for the last two months.
Byram will allow Antonio to move forward to his attacking role and give the Hammers a more solid shape.