Alysa Liu’s gold-medal grin comes with hardware.

Millions of viewers tuned in to watch the 20-year-old win Olympic gold in women’s figure skating on Thursday — and many walked away with the same question: What does she have on her teeth? That flash of silver above her front teeth is a “smiley” piercing, and she did it herself.

Liu’s jewelry is technically a frenulum piercing, a modification that passes through the thin tissue connecting the upper lip to the gums. It’s called a “smiley” because the jewelry stays hidden behind the lip and only appears when the wearer grins wide enough to show the gumline.

“I pierced it a little over two years ago now,” Liu told NBC affiliate TMJ4 News ahead of the Milan Cortina Olympics. “I had my sister hold up my lip, and I was looking in the mirror, and I had my piercing needle and then — yeah, I just put it through.”

The Oakland, Calif., native rated the pain a “zero out of 10.”

Liu picked up piercing as a hobby during the two years she spent away from the sport after retiring at 16. “Getting pierced at a shop is really expensive for no reason. So I thought I would learn it myself, be a little DIY girl,” she explained on the “In The Loop” podcast in 2024. “I trust myself a lot to get it in the right spot placement-wise for the jewelry.”

“I bought all the supplies I would need like piercing needles,” she added. “I don’t do it with, like, safety pins or the piercing gun.”

A professional smiley piercing typically costs between $30 and $100 and heals within four to 12 weeks and can lead to enamel erosion, chipped or cracked teeth and gum recession over time.

The piercing is just one part of Liu’s signature alt-girl look. Her dark brunette hair is interrupted by horizontal bleach-blond stripes, each one added annually like a tree trunk marking the passage of time.

“I originally actually wanted raccoon stripes three years ago, but I was like, ‘Too much, too long and it’s going to be hard to upkeep,’” Liu told reporters before the Games, according to USA Today.

“Then I thought, I kind of want to be a tree, add a new ring every year, and so I did my second one the next year. It just grows out, and then so this year, I just did the same thing. I’m just gonna keep adding one every time.”

She enlisted St. Louis-based stylist Kelsey Miller to brighten the stripes ahead of the US Figure Skating Championships in January.

Liu was born in Clovis, Calif., the eldest of five children. She was raised by her father, Arthur Liu, an attorney and Chinese democracy activist who went into exile in the US in the 1990s, and her mother, Yan Qingxin, also known as Mary.

In 2022, it was reported that Liu and her father had been targeted by Chinese government-directed spies — a revelation the skater has said left her feeling like she was living in a movie.

The two-time Olympic gold medalist scored a career-best 226.79 in Milan to become the first American woman to win individual figure skating gold since Sarah Hughes in 2002.