Pietersen has primarily played as a T20 specialist after being sacked by England following the fallout of their Ashes whitewash last winter.
The 34-year-old captained the Delhi Daredevils in the Indian Premier League earlier this year, has turned out for Surrey in the NatWest T20 Blast and is set to feature for St Lucia Zouks in the Caribbean Premier League, which has already started.
Signing for the Stars, who reached the semi-finals in the last edition, will see him line up alongside compatriot Luke Wright.
''I'm very excited about joining the Melbourne Stars and look forward to playing with some of Australia's best T20 cricketers,'' Pietersen said.
''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 (Melbourne Cricket Ground).''
The tournament usually gets under way in December with the latest edition finishing in February, and a similar schedule this season would mean Pietersen is in Australia while the current England team play a triangular series Down Under, also featuring India, which runs from the middle to the end of next January.
Stars head coach Greg Shipperd said: ''We are delighted to have Kevin as a Melbourne Star. He's a proven competitor and I am confident that he will revel in the fiercely competitive atmosphere of the BBL and will be especially at home at the MCG in front of our loyal Members.''