Special Forces: World’s Toughest Test pushes celebrities to their limits — and season 4 will be no different.

The reality show puts athletes, reality TV stars, musicians and more through a series of tests that the real United States Special Forces completes to become part of the military. While there are no eliminations during the season, contestants can opt to voluntarily turn in their armband and leave the series.

“Everybody comes on the show for a reason. On day one, we look at people and say, in [our] own minds, ‘Why are you here?’ But actually, we know why you’re here,” Directing Staff instructor Billy Billingham told Us Weekly exclusively in a joint January interview with fellow soldier and star Rudy Reyes. “You are here because you’ve lost direction. You need to re-challenge yourself. You wanna be brought back to reality because that’s what this show does.”

Few contestants have passed the course so far, but season 1’s Hannah Brown and Carli Lloyd, season 2’s Nick Viall, Tyler Cameron and Erin Jackson and season 3’s Brody Jenner and Kayla Nicole have all completed the test.

Scroll down for everything to know about Special Forces season 4:

Who’s Competing on ‘Special Forces’ Season 4?

The 18-person cast for season 4 includes Olympian Shawn Johnson East and her husband, Andrew East, as well as married couple Jessie James Decker and Eric Decker.

Reality TV stars including The Real Housewives of New Jersey’s Teresa Giudice and daughter Gia Giudice, The Valley’s Brittany Cartwright, Sister WivesKody Brown and The Real Housewives of Atlanta’s Eva Marcille are also competing on the show.

Rounding out the cast is Kristin Cavallari’s ex Mark Estes, Barstool Sports personality Brianna “Chickenfry” LaPaglia, Jussie Smollett, Randall Cobb, Chanel Iman, Johnny Manziel, Ravi V. Patel, Christie Pearce Rampone and Nick Young.

Where Was ‘Special Forces’ Season 4 Filmed?

Special Forces season 4 was held in Morocco to “endure the extreme circumstances of urban warfare,” according to the season’s description.

“All recruits must learn the art of getting comfortable with being uncomfortable as they are faced with training challenges across the country’s expansive desert terrain, including a supply search in an abandoned village where they must race to extraction, a treacherous rat-run through dark and narrow tunnels, a plane shell dunk drill where pairs of recruits will be submerged underwater and must escape, a death-defying urban ladder crossing between buildings 50 ft above the urban streets, and much more,” the description read.

The past three seasons took place in Jordan, New Zealand and Wales.

When Does ‘Special Forces’ Season 4 Premiere?

Special Forces season 4 premieres on Fox Thursday, September 25, at 9 p.m. ET.