Celebrity SAS: Who Dares Wins viewers are set to see some serious sibling rivalry between brothers AJ and Curtis Pritchard in this week's episode.
The ballroom dancers are both recruits in the current series of the tough Channel 4 show that puts celebrities through special forces training tasks, but if it seemed like they might have an easier ride by taking part together, Sunday's instalment is about to prove otherwise.
Although the Pritchards are each other's biggest supporters in the camp, they are also each other's toughest competition - something the ruthless directing staff decide to play on this week.
The episode begins with former Strictly Come Dancing pro AJ, and Dancing with the Stars and Love Island star Curtis being put in charge of rival teams of celebrities who must push a vehicle out of deep sand, and then run across the desert.
During a late night beasting, Curtis attempts to help out fellow recruit Jennifer Ellison while AJ focusses on his own performance - saying: "Curtis wants to make everybody happy. Curtis wants to help everybody. Curtis wants everybody to pass the finish line together.
"Whereas I'm like, 'no, it's about you'."
But the brother versus brother theme doesn't end there, as later in the episode they face the individual challenge of crossing a ravine on a terrifyingly high wire.
Even though the other recruits have to complete the same task, it is clear that as far as AJ and Curtis are concerned, the competition that matters is between themselves.
As the heat, exhaustion and lack of food and sleep set in, sibling rivalry comes to the fore and tempers begin to fray - but which brother will come out on top?
During a grilling from the staff, Curtis admits that he regrets not having pursued his dancing career competitively after a strong start winning titles.
He says: "When I got to 17, 18 years old, I sort of fell out of love with dancing. I went through 13 different dance partners and I wasn't achieving what I wanted to achieve as fast as I wanted."
Curtis then explains he did a lot of partying with friends instead, adding: "To this day I regret doing that because I didn't achieve goals I should have achieved and didn't reach the level I should have reached, really."
Celebrity SAS: Who Dares Wins airs on Sunday at 9.05pm on Channel 4.
Watch: Kerry Katona says making Celebrity SAS was 'like therapy'