The Hoops faithful were out in full force last Friday night when their side beat Kilmarnock 3-0 at Rugby Park and Forster is expecting more of the same when the Scottish Premiership leaders host St Mirren on Saturday.
A win and favourable results could put Celtic within a victory of clinching a third straight title and Forster feels that the green and white army will again be at the top of their game when the Buddies come Parkhead.
"They have been brilliant - they always are," the Englishman told the Celtic View.
"We have seen how good they are on the Champions League nights and they demand so much of us - they expect us to go out and win, and more times than not we have done that this season and played really well in games.
"Their support is always fantastic and it can be like a 12th man for us so they deserve a big credit, and it will be great if we can go out and win the league and then everyone can celebrate."
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