Justin Bieber is convinced he suffers from attention deficit disorder - because he frequently "drifts off" during his home-schooling sessions.
The Baby hitmaker receives three hours of tuition a day when he is on the road, to ensure his hectic tour schedule does not interfere with his education.
And he admits he's grateful for his personal tutor - because when he tries to learn with a group of classmates, his mind wanders.
Bieber tells The Guardian magazine, "I only have to do three hours a day, which is good. I drift off. I definitely drift off. So I'm better one-on-one... I have a small case of ADD... If I don't understand something, and I'm bored, I don't pay attention.
"So my teacher has to really make it fun for me. Every hour he has to give me a five-to-10-minute break. But after the break I'll be back into it. I'll be good."
Asked if he has been officially diagnosed with the condition, Bieber replies: "No. It's self-claimed."