Pitbull may need to go by "Dale" Earnhardt, Jr. now ... 'cause the party music legend is now a proud co-owner of a NASCAR racing team!!
The Grammy award winner shared the big news on Friday (which also happens to be his 40th birthday) ... officially announcing his partnership with Team Trackhouse and owner Justin Marks.
As it turns out, Mr. Worldwide says he's been a fan of NASCAR ever since he saw the 1990 flick "Days of Thunder" starring Tom Cruise ... and now he couldn't be more pumped to get in on the action.