Villa meet the Mexican giants in their latest preseason friendly in Chicago.
Emery said: "I don’t know exactly (how many), but everybody is telling me there’s a lot of supporters coming from Club América.
“There will be some supporters for us as well.
“We are in America, North America, so for them it is easier to travel and be here.
“And they are playing, as well, different matches against MLS teams here in America.
“Tomorrow, we want to play and test ourselves against them.
“We know some players because some play in Europe, and the level they have here in their league in Mexico is really great.
“Tomorrow is a good test for us, we’re in pre-season, but we’ve lost the first two matches and tomorrow I want to show our best performances with our players.
“Try to compete, try to win, try to adapt to them and try to test how we are against a team like them in that moment.”