Sammy Hagar received one spicy surprise during his Hollywood Walk of Fame ceremony this week ... 'cause his 'Red Hot' buddy Chad Smith showed his love in person.
Sources with direct knowledge tell TMZ ... Smith -- the longtime drummer for the Red Hot Chili Peppers -- came to Hagar's ceremony as a surprise guest Tuesday, and totally shocked the Van Halen frontman.
We're told Sammy went to hug his longtime bandmate, bassist Michael Anthony ... when he realized CS was sitting right beside him.
Smith popped up to hug Sammy ... before joking Hagar really screwed the Red Hot Chili Peppers -- 'cause Guy Fieri's seat was sitting right on top of his own band's star on the boulevard.
The duo later caught up while taking pics with John Mayer and Mike ... a little band reunion of sorts -- 'cause Hagar, Smith and Anthony actually played in the band Chickenfoot together in the late 2000s.
As for post-ceremony ... our sources say Sammy went to grab a bite with a small group of friends and family members at The Polo Lounge at The Beverly Hills Hotel -- which gifted him a giant chocolate guitar.
Just check out the pics ... pretty impressive display, we gotta say -- complete with a ton of tributes to SH's decades-long career from solo artist to Van Halen and a whole lot more.
Seems like a day Hagar will never forget ... and, one he got to experience with some famous friends.