This is a scene from early in the relationship of Neal and Peter. It's from the episode "Forging Bonds."
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Andrew McCarthy guest stars here on White Collar. The shot is courtesy of the 1/25/11 episode of the show.
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Yes, Peter used to don a mustache. What do you think of this look compared to the one we see on him currently?
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White Collar Season 2 Episode 11 Quotes

Often the things we try to hide are most obvious to the people around us.

Vincent Adler [to Neal]

James Bond - shaken, not stirred.

Neal