Dennis Quaid Throws Block Party for Brentwood Neighbors

Dennis Quaid threw a block party Saturday ... and a legendary musician provided essential backup.

Dennis, whose job description can fairly read, "Actor/Musician," had all the trappings for his Brentwood neighbors ... food, drink and music.

Dennis and his band performed, with a special guest ... Robby Krieger from The Doors played guitar for the blues and rock set.  Robby and Dennis aren't strangers ... they've played together before.

Dennis' fiancee, Laura Savoie, was cheering with approval from the sidelines.