Mutya Buena has dismissed speculation the lyrics of her new single are an attack on her Sugababes replacement Amelle Berrabah. The singer - whose new single Song 4 Mutya includes the line 'Is that who has replaced me? - what a diss?' - insists it's not a reference to her substitute. She says, "I've had to do a lot of explaining because of that line but it's got nothing to do with Amelle or the girls." Buena left the girl group in December 2005.