Julia Roberts -- American Sweetheart ... Meets American Pharoah

So, was this a bigger thrill for the movie star ... or the horse?

Two of the world's most beloved beings came face to long face in Santa Anita on Thursday when Julia Roberts greeted Triple Crown winner American Pharoah as he returned to his barn.

AP touched down in California after a flight from Kentucky ... and reportedly got a 6-unit police escort from the airport to Santa Anita ... where he was greeted by Roberts and her son.

FYI -- Julia was 33-years-old when she won her biggest prize in her field. Pharoah was 3.

Point, horse.