Celebrity birthdays: 5 things you didn’t know about Christina Aguilera

As the singer turns 33, celebrate with unusual Christina Aguilera facts!

Celebrate Christina Aguilera's 33rd birthday with little-known trivia about the singer and 'The Voice USA' coach, from her piercings and politics to her 'Method singing' and video ban.

1. Christina had plenty of piercings

Christina racked up loads of piercings, from the standard ears, eyebrow, belly button, lip and tongue to the more intimate areas of her body. They even set off alarms at an American airport.

She told The Sun that she got them done because she was "rebelling" and it was a release during difficult times, but once that had passed the singer had 11 of them removed.

Which one did she spare? The one in her right nipple because, she explained, "that's for me".

2. Christina is politically minded

Back in 2008, Christina starred in a public service advertising (PSA) campaign to encourage young Americans to register to vote in the election that November.

Her Rock the Vote ad campaign opened with Christina singing a lullaby version of 'America the Beautiful' to her then newborn son Max, who was wrapped up in an American Flag.

Definitely an image worthy of the family photo album.

3. Christina is planning a business empire

The singer has her own fragrances, cosmetics and shoe line to name but a few, but that's not all.

Christina apparently requested approval from the US Patent and Trademark Office for more than 450 items. So what could Christina bring out in the future? Crayons, ropes and handcuffs. Interesting.

4. Christina's video ban

Christina's 'Dirrty' was a pretty raunchy video back in 2002, but it wasn't the grinding that caused the video to be banned in Thailand; it was actually the signs on the wall behind the boxing ring.

Time Entertainment reports that the signs in Thai translate to "Thailand's sex tourism" and "Young underage girls". Christina's record label said the singer didn't know what the signs meant.

5. Christina does 'Method singing'

We've all heard of Method acting, but have you heard of Method singing? Well, it exists. According to Christina anyway.

When recording her record 'Back to Basics' Christina listened to Etta James, Billie Holiday, Ella Fitzgerald and Eartha Kitt, and that era of jazz also inspired her new look.

She told the New York Times that the visual's as important as the music, and she wouldn't record without wearing red lipstick: "It was my way of getting into character, sort of like Method singing". Amazing.