Erling Haaland thanked Mateo Kovacic for a happy birthday song as he shared footage of the Croat singing his initiation song on his social media.
The City team are currently in Japan for pre-season after their squad reunited following breaks for the summer, and will face J League side Yokohama FM in their first game of pre-season on Sunday.
As is tradition with many players when they join a new club, Kovacic used what appeared to be a team meal to perform his initiation song, giving his rendition of Steve Holy's 'Good Morning Beautiful'.
Though City will hope Kovacic will perform better on the field than on the microphone, the 29-year-old received a rapturous round of applause from his new team-mates.
The squad were celebrating star forward Haaland's birthday in Japan, with the Norwegian turning 23 on Friday.
Kovacic joined City from Chelsea for £25million this summer with City having to add players to their treble-winning squad with a few departures expected.
Their former captain, Ilkay Gundogan, has already left, with Riyad Mahrez set to move to Saudi Arabia soon.
The likes of Aymeric Laporte, Bernardo Silva and Kyle Walker have also been linked with moves away with City tasked with replacing some of their key men if the moves do take place.
Haaland, meanwhile, celebrated his birthday on Friday and was thankful for his team-mates for making his day special while on tour.
Jack Grealish presented the forward with a cake and led the rendition of 'Happy Birthday' with Haaland donning a beaming smile.
Haaland punched the air as the song went on, before clapping at the end of the song and saying 'thank you guys, beautiful cake, nice'.
He refused to blow out the candles, however, with the crowd cheering and laughing as Haaland thanked his team-mates again.