The Shrimpers will host Harry Redknapp's side, relegated from the Premiership last season, on Monday August 22.
It will be a tough test for Tilson's men, who were plying their trade three divisions below the Saints last year - winning the League Two play-offs.
The game will be shown live on Sky Sports, earning £50,000 for the club on top of increased revenue and sponsorship opportunities.
Tilson said: "We couldn't get a tougher draw than that, and it's a great tie for us.
"It's great for the club and for our revenue."
It will be a tough test for Tilson's men, who were plying their trade three divisions below the Saints last year - winning the League Two play-offs.
The game will be shown live on Sky Sports, earning £50,000 for the club on top of increased revenue and sponsorship opportunities.
Tilson said: "We couldn't get a tougher draw than that, and it's a great tie for us.
"It's great for the club and for our revenue."