Well, shut my mouth!

(well,) shut my mouth

colloquial An exclamation of shock, surprise, or incredulity. Well, shut my mouth! I never thought I'd see you around these parts again! A: "Turns out that he was actually my long-lost uncle." B: "Well, shut my mouth. What an incredible story!"
See also: mouth, shut
Farlex Dictionary of Idioms.

Well, shut my mouth!

Rur. I am very surprised! Well, shut my mouth! I didn't know you were in town! Tom: The governor's on the phone and wants to talk to you. Jane: Well, shut my mouth!
See also: shut
McGraw-Hill Dictionary of American Idioms and Phrasal Verbs.
See also:
  • (well,) shut my mouth
  • (well,) bust my buttons
  • Well, bust my buttons!
  • well, dog my cats
  • (well,) dog my cats
  • You couldn't!
  • You wouldn't!
  • get out!
  • get out of here
  • Get out of here!