Hawks manager Lee Bradbury finds himself up against his son Harvey, who is on loan to the Saints from Premier League side Watford.
Bradbury watched his son score on Tuesday night against relegation-threatened Bognor Regis Town at Nyewood Lane in the 2-1 defeat after going on as a second half substitute.
The 19-year-old, who spent three years with Portsmouth, was snapped up by the Hornets after he was released from Fratton Park.
His father admits it is an unusual situation for both of them, and they will both be hoping the other has a bad day tomorrow, especially with so much riding on the match.
Bradbury Snr told the Portsmouth News (www.portsmouth.co.uk): “You always want your kids to do well in whatever they are doing but not this week.
“Usually Harvey and I talk football all the time but we have put an embargo on that until after the game.
“Normally we would chat about his game, his opponents and how to improve.
“It will be strange for him too because he has trained with us a few times, been around the club and knows all the players.
“When we go out there, though, both of us will be wanting to do the best for our own teams.
“We wouldn’t expect any different.
“I was pleased to see him go on as a substitute in midweek and change the game.
“He scored and won a penalty and it will be interesting to see if he starts against us”.