Billie confirmed that it's a tribute to Amy Winehouse. He said he's never met her, but he had an affinity to her through the music she made. He felt that she was the last one left who had some kind of connection to the days of 60's soul music, and that he felt really sad the connection is gone now, and that there's no one left who makes music like that anymore. A really beautiful, sincere song. A lovely tribute.