My four year old daughter has an imaginary friend. Her name changes often and so does where she live. She talks about all the fun stuff she does with this friend and recently decided that she is her cousin ( she only has two cousins and they both boys ). This friend of hers likes everything she likes, she wears princess dresses all the time, never has to eat something she does not to travel the world but has a pet dragon and lives a very adventurous life.
So, is this normal behavior for a child? The answer is yes. It actually means your child is creative and often times they use an imaginary friend has they learn about good and bad. An example of this could be that your child might blame an accident, such as spilling there drink on their friend. Destiny has done this a couple times, we do not make a big deal of it, have her clean up her mess and move on. She has also tried to get away with something ( like watching a show she knows we don’t like her watch ) by telling us her friend does it. We simply remind of the house rules and let it go.
Everything I have read on imaginary friends has said that kids that do have them most likely will have more then one during this stage. There is nothing wrong with letting them indulge in this fantasy, just do not go overboard with it. Let them be creative and have fun with their friend, it is a normal part of childhood and they will outgrow it with time.