The 36-year-old ended a 13-year stay with the Stamford Bridge outfit in July after agreeing to join new MLS outfit New York City on a free transfer, but has now joined the Premier League champions until January.
Lampard is expected be registered for City's Premier League and Champions League squads as he looks to maintain fitness ahead of the MLS season in March 2015, and called the loan move a "fantastic opportunity".
"Joining up with Manchester City is a fantastic opportunity for me to continue to train and play at the top level and make sure I am in top condition for New York City," he told the club' official website.
"This is a new chapter of my career and I'm really excited about the experience.
"I met Manuel and some of the players in New York and I'm looking forward to getting into training and making a contribution for Manchester City ahead of my move over to New York."Lampard becomes City's fourth summer signing, after Willy Caballero, Fernando and Bacary Sagna, and manager Manuel Pellegrini is delighted to be able to call upon Chelsea's all-time record goalscorer.
Pellegrini said: "Frank is a world-class midfielder and this is an opportunity which works perfectly for everyone, the player, Manchester City, and New York City.
"I'm looking forward to working with him and integrating him into our squad. New York have made a fantastic signing by recruiting Frank, and I'm really pleased that we'll be able to have him with us for the first half of our season and help prepare him for his new challenge."
"This is the perfect opportunity for Frank," New York City FC sporting director, Claudio Reyna, added. "He is in great shape following the World Cup, and training and playing with our colleagues in Manchester will enable to Frank to be fit and ready for our inaugural training camp."
The likes of ex-Chelsea manager Carlo Ancelotti and Arsenal boss Arsene Wenger have queried the move, but Jose Mourinho has insisted Lampard can do whatever he wants following the expiry of his contract with the club.