LATEST: Oprah tenor Roberto Alagna has blasted reports he walked off stage mid concert after being booed, insisting his impromptu exit was due to illness. Alagna was starring in an adaptation of VERDI opera AIDA, but was reportedly whistled down by the public on the show's second ever production in Milan and has since withdrawn from the production. However, Alagna insists his exit was due to a medical emergency - he suffered low blood sugar on the night - and plans to sue venue La Scala for damaging his reputation. He explains, "I was fine when I started, but this problem with my metabolism, if I am very emotional or stressed, my system consumes sugars very quickly. "After that happened to me, the sugars went down dramatically. I couldn't stay on my feet, I had to sit. I didn't have the strength." A spokesman for the opera house said Alagna never mentioned feeling unwell after leaving the stage and hasn't turned over any medical certificate to La Scala management.