Kurt Russell Shows Off 'Once Upon a Time in Hollywood' Jacket

Kurt Russell is a huge fan of his latest film ... busting out a super cool piece of swag from the Quentin Tarantino flick he stars in, while hitting up a classic Hollywood haunt for celebs.

We got these pics of Kurt shopping at the Farmers Market at The Grove over the weekend with his grandkids ... no big shocker -- until we got the rear view. He was rocking a jacket with the "Once Upon a Time in Hollywood" logo on the back!!

Kurt's one lucky dude ... costarring with Brad Pitt, Leonardo DiCaprio and Margot Robbie in Quentin's 9th film. As a Hollywood vet, he obviously knows the game -- it's NEVER too early to start promoting and pumping up that box office!

The movie -- about Hollywood in the days of Charles Manson murders -- lands on big screens in July, but it's mostly been shrouded in secrecy. Quentin won't even say who Kurt's playing.

It's kinda fitting ... Kurt stopped by Magee's House of Nuts while proudly displaying the jacket. The stand has been a staple at the Farmers Market for decades, and once upon a time, it was beloved by President Eisenhower and The Beatles.