Two birds one box

We have a nest box which is currently being used by both a great tit and a house sparrow to build in! The sparrow started building first but the great tit came along and started to remove some of the nesting material which it apparently didn't want and then started to bring in it's own material. Both birds are coming in numerous times each day but as yet don't appear to have arrived at the same time. I am curious if anyone knows what the likely outcome will be as I have never seen this before?