The actor played ageing rock and roll legend Billy Mack in the 2003 movie, which also starred Colin Firth, Emma Thompson, Hugh Grant and Keira Knightley.
And Nighy is convinced his appearance in the all-star movie made him "castable" in the U.S. and changed the path of his career.
Speaking to U.K. TV host Kate Garraway, he says, "Love Actually changed the way I go to work. It made me familiar in America, which meant I was castable. I have great fond memories of it and it really did change my professional life."