The Australian hunk, 22, slammed all allegations he's been unfaithful in his romance with the 27-year-old singer.
Simpson insists he and Cyrus are "great" and told Page Six all reports about his alleged infidelity "stupid."
He also talked about his experience spending the holidays with the "Malibu" hitmaker.
“It was a great Christmas out in Nashville,” he told the publication.
Days before Simpson celebrated the merry day with Cyrus and her family, RadarOnline.com exclusively reported he was out partying in New York City's East Village with a group of women.
“I was there between 11:30 p.m. and 2:30 a.m. He was next to me,” a partygoer at the Sister Lounge exclusively told Radar. “Girls were everywhere, surrounding him. He seems to love the attention. He wasn’t trying to brush anyone off, and he was talking and drinking with them.”
“Girls were coming up one by one trying to get close to him. One girl gave him a kiss on the cheek and he just smiled,” the insider continued. “He was on his phone a lot, but also at one point he was sitting in the booth and girls were on both sides, and he was just flirting with them. I didn’t see anyone kiss him on the mouth but then again I wasn’t like focusing on him the whole time.”
The day after Christmas, Simpson and Cyrus hung out at a Nashville restaurant for their romantic date night.