Dwight Howard thought he was ready.

“I'm in good shape. I have thick skin. I've had tough coaches my whole life. So, what's a drill sergeant? How real can this get? Turns out, incredibly real and incredibly hard,” he says.

He’s talking about his stint on the series Special Forces: World’s Toughest Test in which 16 celebrities take on the demanding training used to prep civilians to become Special Forces operatives.

The celebrities joining Howard, who is a current NBC player, on this journey include former MLB catcher Mike Piazza, singer Montell Jordan, TV therapist Dr. Drew Pinsky, performer Mel B., Hannah Brown from The Bachelorette, actress Jaime Lynn Spears, political spokesperson Anthony Scaramucci, former NFL player Danny Amendola, and professional soccer player Carli Lloyd, among others.

Being a professional athlete, Howard says, “I thought I had a leg up. But it turns out, it's what's on the inside that really counts with a test like this.”

Howard says that there was really no way to prepare for the adventure. “I thought that I could go just train like I would train for basketball or anything else. But once you get there in that Wadi Rum desert [in Jordan], we found out that it was no fun.”

Pinsky echoes this sentiment, adding, “I thought I was training properly for it, running hills, with packs on, spending weeks just focusing on that, But, no, no, the DS (drill sergeants) and the Wadi Rum will have its way with you, no matter what.”

Jordan, one of the non-athletes in the group, adds, “I can also say that what you learn in the process is that what's on the inside is eventually going to come out. So, when we're in the desert, it's not external factors or practice or preparation. It's literally whatever is inside is what the DS pulled out of us.”

Mel B. wants viewers to know that when they watch the show that there was no special treatment for the participants. “[Like people thinking that we] didn't have to really strip naked and get in the tank and then roll around in the sand. Yeah, we did. We did everything that we were told to do.”

She adds, “For example, you couldn't walk anywhere, you had to run everywhere. I mean, when did you ever do that, apart from when you were three years old, running everywhere?”

The drill sergeants pulled no punches, says Mel B. “[They] were so direct — no bullshit, no frou‑frou, just, ‘This is how it is.’"

One of those drill sergeants, Mark “Billy” Billingham, chimes in, saying, “You know, the Special Forces world is 1% of the planet. It's a brutal real world, and the show replicates that. It's not telling some tale. It's giving you a sample of what our life is really like. There's an old cliché, ‘Get comfortable with being uncomfortable,’ and that's exactly what you do. There's no Winnebago. There's no breaks. There's no comfort. It's all down to you.”

He admits that the drills sergeants, “are horrible’ but that “there's nothing personal, there's nothing vindictive. We love you all in a very hard, tough way. That's what [this is] about.”

Howard admits that the training was so tough that he thought about quitting, but then, “I looked around and I saw everyone. I'm like, ‘Man, I can't give up. [There’s] a bigger meaning for this.’ And now, I just feel like, whatever I want to do in life, I have the ability to do it.”

The takeaway for Pinsky, he says, was, “Prioritizing relationships, which I thought I already did, but now I really do; and, number two, the DS is in my head all the time yelling at me. If I think I'm tired or I've gone as far as I can, I can now go further. I would have stopped myself in the past, but I keep going.”

The tough tasks, along with the shared experience among the celebrities is what makes the series both unique and relatable, says Jordan. “We experienced something that's extremely difficult to explain to anybody. We haven't been able to share except with each other. We are bonded in that way, and hopefully people will resonate with what we went through. To choose to say yes to [this] process, I think, is a different kind of crazy, but also maybe a different kind of really wanting to see what you're made of, what's on the inside.”

‘Special Forces: World’s Toughest Test’ premieres Wednesday at 8/7c on FOX.