Kate Upton sucking down an ice cold beer at a baseball game might be every man's fantasy -- but the 20-year-old supermodel says she was NOT boozing illegally ... despite a suspicious video clip.
Kate was at a Detroit Tigers game on July 6th -- in Tigers ace Justin Verlander's luxury suite -- when TV cameras spotted her toasting friends with a sudsy beverage.
We all know the formula -- baseball game + luxury box + sudsy beverage = BEER!
But Kate's rep insists that's not what happened ... telling TMZ underaged Kate was not drinking beer, and was only there to take in the game with a friend. The rep would not say what Kate was drinking.
A rep for the Tigers assured us "all patrons who appear to be under 30 years old are ID'd."
No doubt, Kate looks way under 30.
As for Kate being in Verlander's box, and the rumors they're dating -- her rep refused to comment.