Paulina Porizoka has returned.

The 56-year-old model recently took a brief hiatus from Instagram when she jetted off on a "top secret" adventure, but returned to the photo-sharing app on Monday with a steamy picture of herself in bed.

In the pic, Porizkova appears to be nude while under the covers, flashing her legs for her followers while wearing a smile.

She then gushed over her cozy bed in the caption.

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Paulina Porizkova shared a photo of herself wearing nothing but a bedsheet for her return to Instagram.

Paulina Porizkova shared a photo of herself wearing nothing but a bedsheet for her return to Instagram. (Photo by John Parra/Getty Images for Sports Illustrated)

"Mankind’s greatest invention. It’s not fire, it’s not the wheel, it’s not pre-sliced bread…" she wrote. "It’s Incontestably, incontrovertibly, irrefutably - A MATTRESS."

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She added that she's "convinced" that a good mattress is why humans live longer "these days."

The 56-year-old model gushed over her mattress in the caption of her post.

The 56-year-old model gushed over her mattress in the caption of her post. (Photo by John Parra/Getty Images for Sports Illustrated via Getty Images)

"The beauty and wit of middle age is quickly lost if deprived of a comfortable spot to rest ones bones," the model said. "Here’s to the padding which supports us while we slumber- hay or straw, down or feathers, coils or foam- whatever it is- as long as it is there! #sleep #mattress #goodtobeback #stayinginbed."

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The star went on to address her recent absence from the social media platform.

"YES, I’m back and NO, I cannot even whisper of my travails," she teased. "All shall be revealed next spring."

Paulina Porizkova

Porizkova recently took a break from Instagram while on a ‘top secret’ adventure. ( Photo by Santiago Felipe/Getty Images)

On Sept. 30, the star shared a photo of herself sitting on a dark-colored Vespa with her blonde hair flowing over her shoulders and revealed that she'd be taking a break from the app.

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"Aaand, I’m off! Hello all my lovely IG friends, supporters, peeps and even you little trolls," she began in the caption. "I’m off on a grand adventure. Top secret of course, as those things tend to be when done for viewing at a later date. I will miss you all for the next three weeks. I’m excited, terrified, anxious and filled with gratitude for this opportunity."

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She continued: "AND I NEVER RIDE MY VESPA WITHOUT A HELMET. This was just for the shot by my friend @jillgreenberg, who is a frequent backseat passenger and can testify to helmet use."

In Monday's post, Porizkova also responded to a commenter who suggested she show "less skin." 

"You've got brains and wit and a dazzling smile," the social media user wrote in part, to which Porizkova replied: "I'm not old. I'm happily middle aged. And showing the skin of a middle aged woman is exactly my point. Because that is what we don't see enough of. Being my age doesn't mean I should only get to spout cheery wisdom.

"I appreciate your compliment very much, but I will show lots more skin. It [sic] it offends you, you may want to unfollow," she concluded.