Is it possible to use the connect function in another function?

I ask this because I have been getting the error 'Attempt to connect failed: Passed value is not a function.' It doesn't give me which line the error occurs so I don't what I have done wrong. The script for reference:

local Mouse

function onClick()
    local animation = script.Parent.Parent.Humanoid:LoadAnimation(script.Parent.Animation)
    animation:Play()
end

function onEquip(a)
    if Mouse ~= nil then
    Mouse = a
    Mouse.Button1Down:connect(onClick())
    end
end

script.Parent.Equipped:connect(onEquip())