Who is more famous Justin Bieber or Brad Pitt?

Answer 1

There is not enough statistical data to answer this question properly and without the adequate amount of information (via poll or survey data), any answer would simply be opinion based and not a substantial answer.

Answer 2

Brad Pitt and Justin Bieber have different ages and different field of activity.

Movies make a good actor much more famous than a young singer because the interaction with the public is stronger.