Some 12,000 fans descended upon the iconic venue in the British capital Monday night to hear Chan perform twenty five songs from his Mandarin and Cantonese repertoire.
In an interview before the concert, the 37-year-old singer said he was surprised and pleased to have so much international support.
"I never thought I had so many fans in Europe. I heard people are coming from Belgium, Germany, France and Luxembourg and Spain," he said.
"Maybe they're bored," Chan added, joking.
Chan's DUO World Tour, which began in September 2010 in Singapore and has continued across Australia, Asia, Canada and the United States, has an unofficial slogan: "Who the hell is Eason Chan?"
The singer says that was the question a ticket seller asked after he sold out the O2 Arena in around 20 minutes and crashed the venue's servers.
Millions of fans already know the answer: Chan has released 30-plus solo albums and is one of the best-selling Mandarin and Cantonese pop artists.
"It doesn't matter what language you sing in, what makes it universal is the energy that you give out," said Chan.
This was his second appearance on a London stage after performing at the Royal Albert Hall in 2010.
"It didn't hit me ... until I went back to Hong Kong that I actually miss London, being in London," he said. "The crowd is amazing."
The Hong Kong native started his musical career by winning the New Talent Singing Competition in 1995, but expanded quickly into acting. He has starred in more than twenty films and has been nominated for the Hong Kong Golden Horse Awards and the Hong Kong Film Awards.