The 'Domino' singer looked incredible in the floor-length, shimmering silver gown as she walked down the red carpet but she has revealed the dress was really heavy to wear and left her with scratches all over her back by the end of the night.
She said: "The dress was very heavy it was almost a stone (14lbs) it was like going to the gym, it was my way of working out. I had cuts on my back from the little bits on it. But I felt like a princess in it and that's how you're supposed to feel at the Grammys so it's all good."
Jessie felt privileged to be at the ceremony in Los Angeles because she was there to witness her friend Adele win an historic six gongs.
In an interview with UK station Radio 1, the 23-year-old pop star said: "It was an amazing thing to be there and to witness Adele win six, I was so proud, I was just kind of sitting in the audience, waving from afar like a disco ball. It was an amazing week, it was very emotional and I was just very proud to be there representing for British music."
Jessie never got a chance to congratulate Adele at the Grammys so she is hoping to meet up with Adele at the Brit Awards, at which they are both nominated for prizes, next week.
She added: "I didn't see her because she was swamped by people constantly, which is a wonderful thing, but I'm hoping to see her at the BRITs and give her a proper cuddle and a high five and tell her well done."