From Longman Dictionary of Contemporary Englishbe all earsbe all earsinformalINTERESTED to be very keen to hear what someone is going to tell you As soon as I mentioned money, Karen was all ears. → ear
Examples from the Corpus
be all ears• Go ahead, I'm all ears.• Tell me exactly what happened. I'm all ears.• Everyone was all ears as soon as I mentioned a cash prize. 