The court heard Ungermann assaulted a 16-year-old girl while he was in Melbourne filming a series of MasterChef on February 23, 2020.
The two were in a hotel room when Ungermann grabbed the girl, then 16, and pulled her towards him.
She ran out of the room on the phone to her boyfriend and was seen on CCTV leaving the hotel shortly before midnight in a distressed state.
The teenager had "comforted" the celebrity chef after his fiancee, South African media personality Leigh-Anne Williams, broke up with him.
During the night Ungermann and his victim had been drinking sake at a Japanese restaurant before going to a hotel room where they shared a glass of white wine and a cigarette on the balcony.
The 16-year-old had "started to feel the effects of her alcohol consumption" after drinking the sake, prosecutor Kevin Murphy said.
He "became upset" and the teen "comforted" him.
"I'm going to get s***faced," he told her.
Later on, he patted his chest and asked her for a hug and she said no.
He then "pulled her down onto his chest" without her consent, prosecutor Kevin Murphy said.
Where to get help:
• If it's an emergency and you feel that you or someone else is at risk, call 111.
• If you've ever experienced sexual assault or abuse and need to talk to someone call the confidential crisis helpline Safe to Talk on: 0800 044 334 or text 4334. (available 24/7)
• Male Survivors Aotearoa offers a range of confidential support at centres across New Zealand - find your closest one here.
• Mosaic - Tiaki Tangata: 0800 94 22 94 (available 11am - 8pm)
• If you have been abused, remember it's not your fault.