It is true that Michael Jackson used to make prank calls.
It has been said that these prank calls came from the singer's loneliness and his desire to talk to someone in a fun way.
Actor Russell Crowe also commented that Michael Jackson would giggle at the end of these brief prank calls, and in that way to reveal himself.
Another habit of Michael Jackson was to imitate other deep voices in prank calls, as confirmed by Teddy Riley.
Also, on other occasions Michael Jackson would create a whole prank call situation that included several people so as to achieve a specific purpose regarding his career.
Like, the one that resulted in having the American director John Singleton direct the 'Remember The Time' music video.
"It started as a prank. It was a friend of mine, he's no longer with us. His name is Lloyd Avery II. He's from my neighborhood and he called me up late at night. He did a high voice like Michael Jackson…It was all from a prank that I ended up doing it [directing the 'Remember The Time' music video]" (John Singleton)
In other cases, Michael Jackson phoned someone without initially talking on the phone, but only munching his pop corn (like, when he phoned the American producer Pharrell Williams for a potential collaboration on the 'Invincible' album).