Meeting face to face, one presumes. One also presumes there are 'meetings' of a sort already, such as when ringing bro up and partner answers... My mother-in-law did not twig to the fact that Herself and I shared a residence before cohabitation blessing by clergy occurred, despite my answering the phone at all hours of the day if I were the closest to it. Not until about three months before the ceremony, when she came up to see how plans progressed and found me sleeping in the bed (I worked Night Shift those days).
You make the bold assumption that I ever speak to my brother on the phone. We're not close - it's not that there's any great family drama, we're just very different people with not a whole lot in common except for having the same parents. So yes, this is the first time I will have ever spoken to her.