The ex-Royal Marine, who rose to fame on the reality series, was dropped by Channel 4 earlier this year due to his "personal conduct", but still appears in the latest series of Who Dares Wins which was filmed before his exit.
Middleton, 40, shared an image of himself brandishing a sword in front of his former UK co-stars on Instagram.
He captioned the image: "Now you can see exactly what I’ve been fighting against the past couple of years! I will always fight for authenticity and against any political agenda forced into my work!
"I will continue to fight it with a readied sword whilst never being afraid to lead the charge! Unfortunately I fought this battle alone and you can clearly see now that I was pushed before I jumped... I am not and never will be a YES man so if you want real, then you know where to come!
"Huge respect and gratitude to @channel7 here in Australia for giving me back control of my show and making @sasaustralia BY FAR the toughest and most authentic show on the planet! So proud to be part of the family! #realrecognisereal #leadingfromthefront #firstmanin #chiefinstructor."
The sixth series of SAS: Who Dares Wins launched on Sunday, 9 May on Channel 4, featuring Middleton, along with the show's first ever trans-contestant, 32-year-old Holly from Manchester.
Middleton previously blamed "woke culture" for Channel 4's decision not to renew his contract.
He said: "If you're a snowflake, if you're easily offended – you do not belong on the set of SAS: Who Dares Wins. This is not Celebrity Big Brother – even though it's turned into that.
"You've got a group of military alpha males that are going to put people through a gruelling process. And if you don't like what you see then don't come and work on the set.
"But now it's turned into this PC, woke, everyone in their safety bubble – if you hear anything that offends you make sure you complain. That's a show gone. It's a reality show now. The PC patrol and the woke patrol have taken over."
The father-of-five – who resigned from his role as the Royal Navy’s chief cadet last year – came under criticism for comments he made about the Black Lives Matter protests as well as the coronavirus pandemic. He later apologised for both social media posts.
Middleton joined the army at the age of 17 in 1998 and served for 14 years. He served four years of a 14-month prison sentence in 2013 for unlawful wounding and common assault on two police officers outside a nightclub in Essex.
Watch: What is it like to be Ant Middleton for a day?