Kirsten Dunst VIOLATED the "Jeremy Piven Guide to Rock Concerts" last night ... sporting a Tom Petty and the Heartbreakers T-shirt to a Tom Petty and the Heartbreakers concert.
Congratulations Kirsten ... you're officially "That Guy."
Shoulda watched "PCU" before the show ...
Major Fashion No-No
At The Tom Petty Show
6/4/2013 12:25 PM PDT BY TMZ STAFF
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