We've had a fantastic response,' he said, grinning from ear to ear.
(usually in continuous tenses)
smile from ear to ear
To have a broad, enthusiastic smile. Tim was smiling from ear to ear when his bosses praised him during the ceremony.The kids ran around the beach in a happy frenzy, both of them smiling from ear to ear.
beam/grin/smile from ear to ˈear
be smiling, etc. a lot because you are very pleased about something: I like your graduation photo, with you grinning from ear to ear and your parents looking so proud.