Pop star Lady Gaga's former friend Perez Hilton says she was "poisoned by fame".

Gaga was championed by gossip blogger Hilton at the start of her career but the pair had a bitter feud and he thinks the main reason they fell out was because fame changed her, reports contactmusic.com.

The blogger, whose real name is Mario Lavandeira Jr, says he was hanging out with Gaga in Sydney, Australia when they fell out and she was taking part in a special he was filming, which included a cooking demonstration with the 28-year-old star.

During an appearance on Australian talk show `Mornings`, he told hosts Sonia Kruger and David Campbell: `Actually, all the drama went down in Australia in the summer of 2011. She proceeded to get obliterated drunk, drinking Jameson, and she was a surprisingly functioning drunk woman.`

Asked if he thought it was the alcohol which made her react the way she did, he replied: `No, I think it was fame that just poisoned her. She had an album 'Fame Monster', her second album, and she became consumed by that which she was fascinated about. You know, fame can be a very deadly drug and it has damaged her personally.`