Initialising a KeyValuePair Array

This seems like a straightforward thing to do, but I don't seem to be able to work out the correct syntax. I currently have this:

KeyValuePair<string, string>[] kvpArr = new KeyValuePair<string,string>[];

However, this seems to work:

KeyValuePair<string, string>[] kvpArr = new KeyValuePair<string,string>[10];

But I don't know the size of the array initially. I know I can use a list of KVPs and I probably will, but I just wanted to know how / if this could actually be done.