Olise has made four appearances since signing for the club this summer, scoring against Leicester City as a substitute earlier this month.
Ayew is named on the bench alongside Wilfried Zaha, who has returned for this clash after being rested on Monday night against Arsenal. He replaces Martin Kelly among the substitutes.
There are no other changes to the team which drew with the Gunners, with Odsonne Edouard and Christian Benteke retaining their attacking roles in an offensive-minded XI.
Frontmen Callum Wilson and Allan Saint-Maximin both start in Newcastle's first game without Steve Bruce in charge since summer 2019. The pair have earned five goals and three assists in 13 appearances between them.
Former assistant manager Graeme Jones will lead the Magpies this afternoon.
Palace: Guaita, Mitchell, Andersen, Guéhi, Ward, Milivojevic, McArthur, Gallagher, Olise, Benteke, Edouard.
Subs: Butland, Tomkins, Clyne, Schlupp, Hughes, Kouyaté, Ayew, Zaha, Mateta.
Newcastle: Darlow, Clark, Lascelles, Ritchie, Hayden, Krafth, Manquillo, Fraser, Longstaff, Saint-Maximin, Wilson.
Subs: Gillespie, Schär, Joelinton, Lewis, Hendrick, Murphy, Almirón, Willock, Gayle.