Millwall and Brighton meet for the first time in four years on Sunday when they clash at The Den.
The Lions will be in good spirit going into the game having already knocked out Premier League opposition in previous rounds of the FA Cup in the likes of Everton.
They head into the game fresh off the back of a 2-0 win away at Birmingham City.
Brighton also head into the game in good spirit's having won back-to-back games in the Premier League for the first time since December.
Millwall will be without brace scorer against Ben Thompson, who is cup-tied after featuring for Portsmouth when on loan there earlier in the competition.
The hosts are also assessing the fitness of top scorer, Lee Gregory who was forced on in the second half with a tight calf.
Brighton could well come up against a familiar face with former winger, Jiri Skalak set to be on the bench at least for the hosts.
This is how Millwall could lineup if Gregory is fit: Martin; Romeo, Pearce, Cooper, Meredith; J.Wallace, Leonard, Tunnicliffe, Ferguson; Gregory, Elliott.
The Seagulls will be without Florin Andone (groin) and Pascal Gross (hamstring) for the tie.
However, Leon Balogun is back in training after being missing over the last weeks with a shoulder problem.
Brighton could lineup as follows: Button, Bruno, Dunk, Burn, Bong, Propper, Stephens, Kayal, March, Murray and Jahanbakhsh.
This lineup may well be well off though with manager Chris Hughton having plenty of options to pick from.
Could Murray help fire Brighton to Wembley
Brighton could well be reliant on top scorer Glenn Murray providing the difference and firing them to the FA Cup Semi-Finals.
Murray has scored 13 goals in all competitions this season, having scored the opening goal against former club against Crystal Palace last week in a 2-1 at Selhurst Park.
The 35-year-old striker is all one goal off equalling the tally he managed in all competitions last season and he shows no signs of declining in terms of goal-scoring and how key he is to Albion.
Murray has shown how key he can be already to Brighton in the Cup this season, when he came off the bench in the 3-1 win at West Bromwich Albion in the fifth-round reply and scored two goals in 13 minutes to send Brighton through.
Brighton will have to be wary of threats across the pitch for Millwall
The Seagulls will have to be very wary of the threat Millwall can pose all across the pitch.
As mentioned above top goalscorer Gregory with 11 goals will be a threat. They also have Jed Wallace, who has chipped in with five goals this season.
Then at the back, you have another big threat, quite literally, in 6-foot 4-inch defender Jake Cooper, who has scored six goals and has seven assists this season.