He still felt sick on the day of his show in Manila and saw a doctor, who reportedly diagnosed him with a chest infection and advised him to rest, but the star refused to cancel his appearance.
An insider tells celebrity blogger Perez Hilton, "Justin was advised to either cancel the show or do an abbreviated set. But he insisted on going on. So they cut down the show, but once the show started he kept going."
Bieber managed to complete the 90-minute set, but he had to keep running backstage and was seen "vomiting... in between songs", according to the website.
In a post on Twitter after the gig, Bieber writes, "That show was great but tough. Real sick. Time to rest... Even when I'm sick (it) feels good to come on here and see the love. Gonna rest up and hope to get better. I thank you."