A game between Speroni's previous club Dundee and past and present Eagles players will take place on Wednesday afternoon at Selhurst Park.
Mark Williams, a member of the committee behind the organisation of Speroni's testimonial, revealed that ex-Palace hero Morrison has confirmed his participation for the game.
"The players that Julian has found out about and I can announce: number one, Clinton Morrison has been asked and is really buzzing about it," Williams told the club's official website.
"When we phoned him up to say 'Clinton, do you want to play a game?' He said, 'Damn right, Speroni can't sell out Selhurst Park, you need my name on the posters and the tickets!' It'll be sell out Selhurst if Clinton's playing, so he was great."
The Argentine goalkeeper has made over 380 appearances for the club since arriving in south London in 2004 while 35-year old Morrison, currently with Exeter City, scored 64 goals over two spells with the Eagles in the late 1990s and early 2000s.