Mischa Barton was said to be devastated after hearing about a recent Twitter post from ex-boyfriend Brandon Davis that made cruel comments about her weight. But now, Brandon tells In Touch exclusively that not only did he not make the taunts, he doesn't even have a Twitter account! "I would never say anything nasty about Mischa, especially about her weight," the oil heir tells In Touch. “I am pissed that someone stole my identity and started Twittering things." Even his friend Michele Gargani knows he doesn’t do the whole Internet thing: "He has no clue what Twitter is, so it is obviously a fake account." One insider reports that Mischa has been offered $100,000 to publicly lose weight with Jenny Craig, although the company denies that claim. Besides, says the insider, "Mischa's not that fat and is working out with a trainer to get her body back to what it was before."