like a bolt out of the blue
Unexpectedly or surprisingly; without warning. We always thought of Michael as a life-long bachelor, so it was like a bolt out of the blue when he returned from his vacation sporting a wedding ring! News that they were going to dissolve our company came like a bolt out of the blue. We're all still in shock from it.
like a bolt out of the blue
and like a bolt from the blueFig. suddenly and without warning. (Alludes to a bolt of lightning coming out of a clear blue sky.) The news came to us like a bolt from the blue. Like a bolt out of the blue, the boss came and fired us all.