'Till The World Ends' superstar Britney Spears has revealed that watching her music videos back is almost like having an out-of-body experience because she is always taken back by her on-screen transformations. 

She has recently finished shooting the promo clip for her new single, 'Work Bitch', and told E! News that acting like a bad girl was challenging, but she was shown the final result and couldn't believe her eyes:

"When I watch playbacks sometimes, I'm like, 'Who do I think I am?! Who the hell do I think I am?!"

Speaking about the new video, Spears confessed that stepping out of the role of mother and caregiver was tough as she had to portray a "nasty bitch mommy" although she managed to step into character eventually:

"My choreographer actually, when I was doing the rehearsals for this video, he was like, 'Britney, you are not a sweet mommy in this video. You are nasty bitch mommy in this video.' And I was like, 'Ok... Ok!' When you start to feel the character, you start to feel silly, 'cause you're like, 'This isn't me, I'm not like this.' Moving all sexually and stuff like that... As a mommy you feel really awkward doing that."