Prince Harry is getting the shock of his life as he is forced to endure temperatures as low as minus 45 degrees Celsius in the UK.
The unsuspecting Prince is being bombarded with blizzards, high winds and sudden, extreme drops in temperature in a test chamber in the Midlands.
"For the next 24 hours Prince Harry's living in conditions where if he took off his gloves he'd suffer frost bite in minutes", explained Alex Rayner, who's working with the Walking With The Wounded South Pole Allied Challenge.
Members of Prince Harry's team have been given special telemetry pills to swallow, which are designed to feed data to a computer assessing core body temperature.
It is understood the Prince did not take one of the ingestible thermometer pills.
The team arrived at the Midlands test chamber at 9am for a thorough kit check before undergoing a full medical examination.
"So far this morning the chamber temperature has been taken down to -35 degrees Celsius, with a wind speed of 60mph", explained Emily Conrad-Pickles.
"And just a short while ago Prince Harry and the team began putting up the tent, so the wind speed's been turned up to really test them."
While in MIRA's environmental test centre in Nuneaton, all members of the team will have probes attached to them to monitor their heart rate and skin temperature.
The gruelling 208-mile (335km) trek to the South Pole for charity will see Harry and the team placed under extreme physical pressure.
To collect accurate data during the next 24 hours, the Prince will be required to use an exercise bike and ski on a cross-trainer for up to 15km.
"This will help the team members individually work out how many layers they need to wear when they are hot, but at the same time to avoid getting too cold," added Ms Conrad-Pickles.
Prince Harry and his fellow teammates are due to dismantle their tent and emerge from the chamber on Tuesday morning.