Celebrity photographer Rankin Waddell has branded pint-sized powerhouse Christina Aguilera as the most nasty celebrity he has ever worked with.

Rankin, who has worked with celebs like supemodel Kate Moss and the Material Girl Madonna, says notorious diva Christina was simply a nightmare to work with.

“Christina Aguilera, I think is a really horrible, nasty person and I would never work with her again.” Why? “Because she’s not nice. She’s just not a nice person. She was pregnant when I shot her so maybe she was having a bad day. But I don’t think so,” retorts the shutterbug once branded the bad boy of the photography world.

“…She’s very cold and quite rude. I didn’t like the way she treated people around her. I don’t care if she gets to know it either.”

“Christina was a diva from hell and pure torture to be around. She’s so self-obsessed,” Rankin adds. “She insisted her chauffeur drive her indoors into the studio so she wasn’t papped — even though there was nobody outside. Then she crashed my after-party and her bodyguard stood outside the bathroom shouting: ‘Nobody but Christina uses this toilet.’”