It's starting to seem like Zac Efron might be allergic to shirts.
The 28-year-old star, who loves to show off his insane abs, flashed his toned physique and massive biceps in a pic he posted to Twitter on Thursday.
WATCH: The 27 Most Important Shirtless Zac Efron Pictures
"I woke up like this," Efron wrote along with a photo of himself getting styled in the green room before his appearance on Jimmy Kimmel Live!, promoting his new film Dirty Grandpa.
WATCH: Dwayne Johnson Admires Zac Efron's Buff Bod: 'Nice Tits Brother'
It's unclear if Efron means that he sleeps in denim jeans or if he wakes up with a woman running her hand through his hair, but both are possible.
Much of the ad campaign for Dirty Grandpa revolves around Efron being half-naked throughout the movie, so it's not surprising to see he's stripped off his shirt for more free press, but you have to admire those arms.
WATCH: 'Neighbors 2' Trailer Is Hilarious With the Return of Zac Efron (Who Still Can't Find His Shirt)
He's come a long way since his days on High School Musical, which is perhaps why he didn't show up for the show's 10th anniversary reunion on Wednesday. Or maybe Disney wouldn't let him show up topless, and Efron wasn't having it. We may never know.
For more on Efron's love of going shirtless for movies, including his upcoming comedy sequel Neighbors 2: Sorority Rising, check out the video below.