Mark was speaking to Sunrise newsreader Sally Bowrey and hosts Nat Barr and Kochie about the footy when Kochie said, "Berets you're a bit high".
The camera then showed the sports presenter squatting behind the desk as he did not have a chair.
"Gee, it's a tough workout on the quads," Mark said.
The hosts laughed as Sally was impressed by his form.
"Nice squat, good form," she said.
"Hold that will you," Kochie added.
Mark then joked if he clicked his fingers a chair would appear and clicked multiple times before a chair is brought over.
"Who needs a chair, they're overrated," Mark says before Nat responds, "Hard to get good help these days."
Sunrise posted a clip of the moment on Instagram, with fans also impressed by Mark's core strength.
"He's doing fine, he is strengthening his legs," one said.
"Sunrise keepin' it real," another commented.
Nat gives fans a sneak peek under the desk
It comes after Nat gave viewers a sneak peek under the desk in May, revealing she had multiple heaters near her feet.
“Me whinging about how cold it is = check. Sorry Kochie and Beretts!” she wrote.
Natalie went on to complain about how cold the studio was in the comments, telling a fan that the studio is never heated properly.
“I had 3 thermals on this morning. The studio is freezing,” she replied to one of her followers.
Never miss a thing. Sign up to Yahoo Lifestyle’s daily newsletter.
Or if you have a story idea, email us at firstname.lastname@example.org.