No team lineups have been published for this match yet. Team lineups are generally announced in the hour leading up to kick off. In the meantime, here's how the teams lined up in their previous fixtures:
Southampton could become the first team to knock Arsenal out of both domestic cups in the same season since Manchester United in 1982/83.
Arsenal have progressed from 16 of their 20 FA Cup Fourth Round ties under Arsene Wenger, losing only to Leeds (1996/97), Leicester (1999/2000), Bolton (2005/06) and Stoke (2009/10).
Southampton have kept clean sheets in four of their last five games against Arsenal in all competitions.
The Gunners have won their last five away FA Cup matches in a row – they have never won six consecutively in the competition's history.
This is the first FA Cup meeting between Arsenal and Southampton since the 2003 final, which the Gunners won 1-0 courtesy of a Robert Pires goal.
Southampton have never beaten Arsenal in an FA Cup tie (Semi-final in 1926/27, Sixth Round in 1978/79 and the final in 2002/03).
After losing back-to-back games against Everton and Man City, the Gunners have since gone six games unbeaten in all competitions (W5 D1).