Justin Bieber once stole his teacher’s pen so he could change his grade on an exam. The 16-year-old Canadian pop star has been home-schooled since he shot to fame last year. He loves not having to go to school everyday, but enjoys reminiscing about some of his naughtier escapades. The star says he used to lie all the time, and even changed his fail grade to a pass so his mother wouldn’t find out how badly he had done in an exam. “I tell a lot of lies,” Justin told Top of the Pops magazine. “A couple of years ago. I had an F grade on a test at school, but I turned it into a B with the teacher’s pen!“My mom had to sign that she’d seen it before I took it back, so she had no idea how bad it actually was!” Justin has also lied to his mother about more trivial things. He once told her he had handmade a cake for her birthday, when he had in fact purchased it from a local shop. “It’s not the first time I’ve lied,” he laughed. “I told her I’d baked her a cake for her birthday once, but I really just bought it from a baker. I would’ve if I knew how, but I was afraid I’d mess it up.”