The Joker from Persona 5 will appear in Persona 3 Reload: Episode Aigis - The Answer

Atlus announced at Gamescom Opening Night Live that the Joker character from Persona 5 will be included in the Persona 3 Reload - Episode Aigis - The Answer expansion pack:

Here's What We Know

The Joker will be powered by the character Arsen from Persona 5 and will perform powerful attacks, including Sataniel. This crossover is part of the Persona 3 special content, which also included the participation of characters from Persona 4 in Persona 5 Royal.

Persona 3 Reload - Episode Aigis - The Answer will be released on 10 September on various platforms. The story begins where the original game left off, with the special forces finding themselves in a mysterious time loop. The heroes must make their way into the Abyss of Time to find a way out.

Source: GamingBolt