Dynamically change the color of a polygon in leaflet?

[NovaDev]

For anyone who is familiar with Leaflet, do you know a way to dynamically change a polygon's color? For example, take a circle defined like this:\[code\]window.circle = L.circle([51.508, -0.11], 500, {color: 'red',fillColor: '#ffffff', fillOpacity: 0.5}).addTo(map);\[/code\]Then later, after a user clicks a button somewhere on an interface (for example), I want to change the color of the circle like this:\[code\]window.circle.options.fillColor = "#dddddd";\[/code\]The code changes the value for window.circle.options.fillColor, but the change is not reflected by a change to the color of the polygon on the map. I've searched around but haven't found anything. Any ideas?Thanks.