"It was very emotional for me. I always think it's important to wear something which is emotional to you," she added.
Even though people are ready to lend her a lot of things to wear, Mendes prefers something of her own.
"Everybody always wants to lend you things for these events and stuff and it's all wonderful and you give it back at the end of the night, but I like to have a little emotional piece with me," she said.