They were selling the stickers at the show in Hasselt…

The t-shirt has the symbol Om on it. If you’re interested in the meaning of it, you can check out this page: http://hinduism.about.com/religion/hinduism/library/weekly/aa022200.htm
At some of the pictures you can also see J has some kind of beads-string round his arm.
And reading the lyrics of the last album, J has obviously embarked on some kind of religious path…