Gwyneth Paltrow makes ''orgasmic noises'' when she has a pedicure.

Celebrity nail artist Sophy Robson admits she was a bit star-struck when she asked to treat the 'Iron Man 3' star's feet but was reassured by the actress' friendly nature, and surprised by just how much she enjoyed the treatment.

Sophy said: ''When I was working at the nail bar, a couple of celebrities used to come in and the one that really left me star-struck was Gwyneth Paltrow.

''I was really nervous and I remember doing her pedicure and thinking, 'I've got Gwyneth Paltrow's foot in my hand!' Somehow I managed to keep my cool. It helped that she was really nice too, although I was giving her a foot massage and she was making all these orgasmic noises.''

While Sophy had a good experience with Gwyneth Paltrow, it wasn't so pleasant working for ''very difficult'' Christina Aguilera.

Speaking to LOOK magazine, she said: ''I remember being called up to do Christina Aguilera's nails the night before she was going on [TV show] 'CD:UK'.

''These big American celebs were used to getting their nails done at the click of a finger and they would come to London and expect the same. It definitely wasn't the best experience - she was very, very difficult.''