First, the leader needs to have the guts to stand out and be mocked.
A leader's first follower has a crucial role: he will show everyone else how to follow.
Next, the leader embraces the first follower as an equal. Now it's not about the leader anymore but about them.
They will call their friends, and each one that follows will add to the movement. New followers will emulate the followers, not the leader.
After a few more people join, you've got momentum. The more people join, the less risky it seems as they won't be ridiculed or stand out. They'll be part of the in-crowd.