Oscar De La Hoya just got his first MAJOR political endorsement -- with former Mexico president Vicente Fox telling TMZ Sports, "I'm with you all the way!!!"
"Breaking news! Oscar De La Hoya is running for President of the United States. Bravo Oscar! You will make it," Fox told us.
Technically, Oscar isn't running yet -- but he told TMZ earlier this week he was putting together an exploratory team to see if he could get enough support to make a serious run for the White House in 2020.