Fans spotted the musician opting out of the celebrations after City’s third goal at Craven Cottage.
2
Gallagher was amongst the travelling supporters in the away end on Saturday.
City claimed a 4-0 victory in the early kick-off to move top of the Premier League.
Josko Gvardiol scored either side of Phil Foden’s stike but chose not to take a penalty in stoppage time to complete his hat-trick.
Instead, Julian Alvarez converted from 12 yards to add a fourth for the treble winners.
City’s fans pulled out their popular Poznan celebration after Gvardiol’s second goal.
The supporters turned the backs to the pitch to jump up and down shoulder-to-shoulder.
However, Gallagher appeared to be the only person not joining in.
Television cameras picked up the former Oasis star facing forwards and looking around as those around him bounced up and down.
CASINO SPECIAL – BEST CASINO WELCOME OFFERS
City fans adopted the Poznan after copying the celebration during a Europa League clash with Lech Poznan in 2010.
The Polish club are understood to have founded the celebration, which is popular amongst supporters in Eastern Europe.
Fans had plenty to celebrate on Saturday as Pep Guardiola’s side leapfrogged Arsenal at the top of the table.
City are now two points clear ahead of the Gunners’ trip to Old Trafford on Sunday.
Meanwhile, the defending champions have a game in hand against Tottenham on Tuesday before ending the season at home to West Ham next weekend.