Gomez was sitting in Bieber's lap and the two were engaged in deep conversation and looked very much in love.
After this, a fan started writing on Twitter: "I am disgusted".
A fan known as Strongforjieber wrote: "Go back to your own friends and family. Let Justin breath and get your tongue from down his throat @selenagomez."
Gomez had broken up with Bieber after he was seen flirting with models at Victoria Secrets event.
The couple eventually got back together again. But fans have questioned Bieber's dignity.
"Oh wow. that's obviously how he thanks her for humiliating him in public. do you have a bit of dignity left?" CatchThatBieber tweeted.
"Your relationship is faker than Joan Rivers face @justinbieber @selenagomez" Michelle wrote.