Gwyneth Paltrow will never forget her first meeting with personal trainer Tracy Anderson - the fitness guru made her strip off for a harsh appraisal.

The Shakespeare in Love star has credited the exercise expert with helping her shed the stubborn baby weight she gained while pregnant with son Moses.

But the Oscar winner admits she was taken aback by Anderson's no-nonsense methods after she made her new client bare all.

Paltrow recalls, "With my daughter it had been easier (to lose weight), but this time, no matter what I did, I felt stuck. I couldn't shift the weight. But I met Tracy and she was this force from the second I met her.

"She pulled my pants off. I'll never forget it. She was like, 'Oh, my God, wow, I just am so surprised, because you look so good in clothes. I wasn't expecting this.'"

However, Paltrow insists Anderson's regimen put the spark back into her marriage to rocker Chris Martin, telling Redbook magazine, "It did such wonders for my life, my confidence, my sex life, everything."