"Aquaman" star Amber Heard made a splash – pun completely intended – at the London premiere of her new superhero movie last week by wearing a nifty Valentino couture swim cap to go with her matching green-and-gold gown.

It matched the underwater theme of her character, Atlantean warrior princess Mera, who is Jason Momoa's Aqua-love interest. But Heard tells USA TODAY she was a little bummed she didn't get to keep the dazzling headwear.

"I wish. Admittedly, I'm not going to lie: There's nothing I like more than some impractical piece of fashion – an impractical item in general that I have to add to the collection of things I have to lug around," Heard says during an interview for "Aquaman" (in theaters Dec. 21). "Even me, I was like, 'Well, it's not like I'm going to wear it again,' but I wanted to keep it because it was so cool!"

Heard gets a quite a few costume changes as Mera, including one bit of regally fishy fashion to go with her usual action-ready ensemble. She was ready to leave all that behind, thank you very much.

"After working for seven and a half months filming this, wearing that costume over 16 hours a day, five days a week, I have to tell you, I wasn't tempted to take anything," Heard says, laughing. "I'm not quite ready to even think about the sequel. I'm not exactly gagging to get back into that costume."

Check out Heard's usual premiere style in the gallery below, which – fingers crossed – will have her rocking bejeweled frog flippers before long.