Ritchie will ironically take the number five shirt previously worn by another "Ritchie" of sorts after Matt's departure to Swindon earlier in the month.
The 22-year-old Belgian is versatile enough to play all across the back four and has already played for Sheffield United and Preston this season, with the latter emergency loan spell terminated when Darren Ferguson (i.e: Sir Alex's son) was sacked.
He has also played for Stoke City (surprise, surprise!) but has only featured for his parent club six times, so it's difficult to judge him there although fans of both the Blades and Preston say he is "OK" defensively but very good going forward.
De Laet is expected to play at left back tomorrow in place of Carl Dickinson although could be pushed into midfield if Steve Cotterill decides to play five in the centre of the park.
Time will tell if this is a good signing but in all honesty he doesn't have to be a great player to be better than Dickinson, does he?
Welcome to Portsmouth, Ritchie!