Scared to tell the bride I'm pregnant

I need to tell my friend whose wedding I'm in that I'm pregnant. And I'm terrified. She's been a bit of a bridezilla and I know she's going to be upset about this complicating the bridesmaid dress situation. (I won't fit in a satin dress at 20weeks) We never talk on the phone, but do I have to call her for this? Can I just chicken out and email her? Stressed!!!