He was turned away from New York's JFK Airport after flying in to appear on the LateShow with David Letterman this week.
He had been due to plug his new movie Forgetting Sarah Marshall on the talk show, but was instead put back on the next plane to the UK.
Brand joked: 'Now that I know what it's like to be an illegal immigrant, I've cancelled my membership to the BNP.'
However, The Sun reports that he did manage to pull an air stewardess on the return journey.
Brand has previously encountered trouble with US border officials because of his old drug convictions; but he would have secured a working visa to film Forgetting Sarah Marshall in Hawaii last year.
