grammatical number - "Couple was" or "couple were" getting married?

I have recently read both:

couple is getting married

couple are getting married

So which is actual usage?

Answer

From Ngrams, you can see that "couple were married" beats "couple was married". This is especially true for British English.

Looking at the Ngram results for American and British English, while both forms are currently used roughly equally often in the U.S., hardly anybody says "the couple is getting married" in the U.K.