Paulina Porizkova wears 'nothing but 20-year-old bikini bottoms' in new photo: 'Time for one of us to retire!'

Paulina Porizkova is showing off an old swimsuit.

As part of a series called "Wednesday Wearables," the 55-year-old model took to Instagram to share a picture of herself -- sans makeup -- simply rocking a pair of bikini bottoms from two decades ago.

"#wednesdaywearables presents: nothin but 20 year old bikini bottoms," she captioned the snapshot on Wednesday. "It’s supposed to be tan-thru since I hate bikini lines, but it never worked all that well. I still liked it for the material dries super fast."

PAULINA PORIZKOVA POSTS MAKEUP-FREE PIC, SAYS SHE FEELS 'INSECURE': 'TRYING TO COME TO TERMS WITH MY AGING'

Porizkova added that she thought the swimwear "was indestructible" until she noticed "black marks that resemble tar," which appeared on her hips and shoulders.

"Couldn’t figure it out for a while - until today- eureka! It’s the black dye coming off," she noted before joking: "Time for one of us to retire!"

Porizkova concluded her post by thanking her social media followers and asking for prayers for her best friend and goddaughter.

"#tanthrubikini #timetoretire #betweenjloandbettywhite #wednesdaywearables THANK YOU ALL you LOVELY INSTAFRIENDS FOR THE SUPPORT AND LOVE," she wrote. "Let’s send out little prayers of light to my bff tracy @tracyrapp and my goddaughter @sarah_rapp and Mimi Rochelle. ❤️❤️"

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Porizkova's social media followers were quick to comment on the post including Sports Illustrated Swimsuit model, Haley Kalil, who wrote: "How are you this perfect," along with a red heart emoji.

Another person wrote: "You are so gorgeous with the most incredible body.... you're a fine wine that just keeps getting better...."

"You are so beautiful, for more reasons than one. Thank you so much for being such an incredible inspiration to all of us," said another person.

Porizkova is known for being open with her fans. Earlier this month, she expressed how she feels unhappy with the way she looks as she ages and how she's trying to get over those feelings.

"This is what 55 looks like- on a good day... Freshly rolled out of bed. Had a good nights sleep (for a change) after a lovely July 4 th weekend," she wrote alongside a selfie with no makeup.

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She continued:  "But also waking up to tragic and sad news of the pandemic - a reminder that that happiness is a butterfly, it’s only a perfect moment in time and like all else, it passes. Disturbing and comforting all at once - nothing good lasts- but nor does anything bad..."

After acknowledging the troubling upticks in reported coronavirus cases, Porizkova poked fun at herself by adding a few hashtags: "#fiftyfiveandcounting #betweenjloandbettywhite #nofilters #nofillers #nobotox YET!"

She went on to explain that her supermodel good looks aren't always enough for her.

"[By the way], posting this photo because I’m super insecure about my appearance- not proud of it! I may have body dysmorphia in the opposite direction: believing I look much better than I actually do," Porizkova admitted.

"I’m so used to looking one way in photos, that this older me that stares back shocks me. By posting myself unaltered, I’m really trying to come to terms with my aging. I figure if I put the real ME out there, I’ll get used to being older - eventually."

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Furthermore, she added: "Also noteworthy- to fix impending jowls- smile."

Porizkova has also previously taken to social media to share bare-faced selfies with her fans.

In May, the model shared a makeup-free picture with her followers, revealing that this is "what I actually look like" in the morning.  And in January, she took to social media to post a snapshot of the "real true me."

Fox News' Nate Day contributed to this report