Pietersen, who was axed from England side, has signed a two-year deal with the Stars. The right-hander replaces Sri Lankan fast bowler Lasith Malinga as Stars' second international player. Malinga has made himself unavailable due to World Cup 2015 preparations. BBL 4 starts in December this year.
"I'm excited about joining the Melbourne Stars and look forward to playing with some of Australia's best T20 cricketers," Pietersen said on BBL's website.
Pietersen joins some of the big hitters in T20 cricket at Stars side. He will be with Glenn Maxwell, David Hussey, Cameron White, Luke Wright and others.
The 34-year-old Pietersen, on his Twitter page, wrote "Aussie, Aussie, Aussie........#boom #melbourne #BigBash #stars."
"Joining the Melbourne Stars was an easy choice for me when you look at the players we have and the amazing off-field support staff, and don't forget our home ground, the MCG," he added.
At this year's Indian Premier League (IPL 7), Pietersen captained Delhi Daredevils.
"KP's an awesome talent and a proven world-class cricketer across all forms of the game," Stars' chairman of selectors, Damien Fleming, said.
"Someone of his experience will be of great benefit to our club as we strive to go one step further in BBL|04."