Filename based on value of cell

Hi

Im making an invoice template and I want to make it really nice and easy for the people that are going to use it.

I have a cell with the 'invoice nr' lets say A1 which would have the value 859

I want that everytime someone hits 'save as' the suggested name is 'invoice 859.xlsx'

I have tried to search for an answer without luck.

It is fairly easy to do?

Thanks!