Parker, 50, wore an Asian-inspired gown with a red and silver Philip Treacy hat you'd have to see to understand.
As for the dress, she told Cosmopolitan.com that there's a sweet story behind the eye-catching ensemble.
"We were pretty deep into the [dress] design, myself and this wonderful tailor here in New York, and then H&M called and they said they have this initiative called Conscious Collection, where they use sustainable fabrics."
She added, "They reuse fabric and vintage pieces and organic cottons. So I said, 'Look, this is where I am in the process, how do you feel?' And they basically dug up every piece of old fabric they could find in Sweden, and it's all been incorporated into this. And I knew I wanted poppies all over, and so we found somebody in New York to hand-embroider all these."