For once my interest in clothing (not fashion per se)
might can come in handy lol
I'm confident that the t-shirt is from a label called "
Junk Food".
They have that vintage look on the t-shirts where it looks like it has been washed 100 times, and they also print the smurfs.
Unfortunately I can't find that exact t-shirt though, and what makes me more unsure about it is that Junk Food doesn't have that fit with the "open neck"/v-neck that Michael's t-shirt has on the picture.
But if you want cute smurfs t-shirts or something similar then definitely look around for the Junk Food t-shirts, they have hundreds and hundreds of different prints, not just smurfs.
They also have a sister brand called "Junk Mail".