"Can I leave you guys to it? I don’t feel very well, excuse me," Gary said as he stood up and walked off set.
Owen tried to pick up the interview but added, "It feels a bit weird now," before apologising and joining his pal.
Donald finished the chat solo.
Gary and Mark returned to perform the band’s latest single, Giants, and Barlow hit Twitter after the show to assure fans, who had flooded social media with their concerns, he was "absolutely fine".
Reports suggest the pop star simply felt a little faint after a day spent promoting the band's hit new album Wonderland.