"This is your final one, and it's really big," Busy said as she directed Jenna to a giant box.
The women counted to three and ripped the lid off the box to uncover the 56-year-old actor hiding inside.
"Oh my God!" Jenna yelled. "I wasn't expecting a human being to be in the box, and on top of that I wasn't expecting that human being to be Steve."
"I'm really sorry," the "Foxcatcher" star laughed, and the pair embraced as an overwhelmed Jenna began to cry.
In a post on Instagram, Busy shared the clip from the show, revealing Steve as the mystery present in the box.
"This is the most surprised I've ever been. OMG. The best," Jenna wrote in the comments.
"The Office" ran for nine seasons from 2005 to 2013, and fans have clamoured for the show to be rebooted.
However, when asked back in November (2018) if he would reprise his role as bumbling office manager Michael Scott in the much-loved U.S. sitcom, Steve was quick to shoot down the rumours.
"It was a great experience. I love all those people, but I just don't think it's the best idea. I think maybe we should just leave it alone," he explained.