While the Oscar winner wasn't thrilled about participating in such an extreme sport, she did tell Harris that she'll still be sending his kids, twins Harper and Gideon, Christmas gifts ...but he's off the list!
Reese isn't the only victim of Harris' show shenanigans. The 42-year-old actor revealed to ET that he's also pranking stars, including the judges of The Voice.
"I was Jurgen Vulmer, who was the host of The Voice Austria, which doesn't exist," he explained, adding that he basically asked the judges a bunch of strange questions. "I had almost three hours of prosthetic makeup on. I looked nothing like myself, and had a different accent."
Best Time Ever airs Tuesday nights on NBC at 10/9 c.