new one on
a new one (on me)
Something I was not aware or informed of or knew nothing about until just now. A: "Yeah, Jeff and Anthony have been going out for a few months now." B: "That's a new one—I thought they were just friends." Having to pay for the water you use in your house is a new one to me—is that an American thing or something?
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
new one on someone something
that one has not heard before and that one is not ready to believe. Bob's talk of poverty is a new one on me. He always seems to have plenty of money. The firm's difficulties are a new one on me. I thought that it was doing very well.
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs. © 2002 by The McGraw-Hill Companies, Inc.