City have secured Lampard in a six-month loan deal.
The 36-year-old will join up with his new City teammates on Wednesday and will be at the Etihad Stadium until January.
Lampard signed for New York City, owned by Manchester City and baseball giants New York Yankees, on July 24.
But the news of his decision to join the Premier League champions will no doubt cause huge disappointment for Australian football fans.
It is not clear whether Lampard would feature regularly in City's first team but the midfielder will be keen to sharpen his fitness before the start of the MLS campaign in March.
City face Chelsea on September 21 in the Premier League and it is possible Lampard will be allowed to sit out of the clash.
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