Miranda Kerr & Justin Bieber Hook-Up Rumors -- Miranda: I Never Slept with Justin

Miranda Kerr did NOT sleep with Justin Bieber after the 2012 Victoria's Secret fashion show ... so Miranda claimed at the time as did her lawyer.

Miranda's lawyer sent out a letter at the time rumors swirled that Miranda and Justin hooked up at a hotel after the show ... when she was still with Orlando Bloom. The letter calls such claims "false and defamatory."

We're told Kerr was as adamant as her lawyer at the time ... that she did NOT hook up with Bieber.

Apparently Orlando Bloom didn't buy the story. The couple separated the following year. And it's very clear from the story we posted Tuesday night ... there's beef between Justin and Orlando over Miranda.

As for Justin ... sources connected with the singer say he got all braggy when he talked about Miranda ... which of course does not necessarily mean he was telling the truth.

Miranda posted a photo this afternoon on Instagram of herself topless in a bathtub ... just in case you forgot what all the fuss was about.