Actor Sterling K Brown, who stars in the show, made the revelation, reported ET online.
"We're in the middle of shooting our Christmas episode right now and I had a scene on Friday night that started at 5pm and we didn't finish till around three in the morning and it was just one scene.
"Helen Hunt is directing it. And it was quite extensive. That's all I can say about it," Brown said.
Hunt has previously helmed several episodes of her hit sitcom "Mad About You," as well as episodes of "alifornication," "Revenge" and "House of Lies," among others.