The actor took 'AGT' fans on a trip down memory lane this week with an impromptu performance of Vanessa Carlton's "A Thousand Miles" ... which he, of course, famously did in the movie.

As good as that cover was on camera all those years ago, this one might be right up there as far as commitment ... 'cause the dude was all in on the lip-synching, not to mention the moves he added for extra gusto.

Check it out — Terry goes all out here, mouthing the lyrics to a T and adding accompanying steps ... ones he might not have had a chance to perform in the flick. You'll recall, his character did the whole 'Thousand Miles' in the confines of a car. So now, we’re getting the full-body number!

The 'Got Talent' crowd ate it up ... they seemed to be singing along, and gave him his props at the end — and how could they not??? This is top-notch entertainment.