In an Ask Me Anything session, the 20-year-old producer-DJ opened up to fans in a video made on his hotel balcony in Mexico City, reported Billboard.
When one of the fans asked him about his recent Australian tour with Bieber, Garrix admitted on being "nervous" initially but said the show was a total hit.
"If I do a Martin Garrix headline show I know it will be lots of Garrix fans etc, but this time I was nervous... It will only be lots of Bieber fans they're only waiting for Justin Bieber.
He added that the feel of the tour was "crazy" and "the fun thing about this tour was I had no idea what to expect".