Flex/AS3 - calling a function dynamically using a String?

Is it possible to call a function in AS3 using a string value as the function name e.g.

var functionName:String = "getDetails";

var instance1:MyObject = new MyObject();

instance1.functionName(); // I know this is so wrong, but it gets the point accross:)

UPDATE

The answer from @Taskinoor on accessing a function is correct:

instance1[functionName]();

And to access a property we would use:

instance1[propertyName]