Bieber invited Jaden to perform after he appeared in his video for Never Say Never.
"Special security arrangements are being made for Jaden, who will appear onstage, and his family, including Will, to be in the audience for the concert," claims a source.
Sean Kingston and Jessica Jarrell will also be guests at the show.
Bieber's MSG show will be filmed for his 3D movie.
Update: Sources tell us that Usher will definitely be there - as well as "many" other celebrity surprise performers!
[Image via WENN.]