'Dancing With the Stars' Cast Expresses 'Disbelief' Over 'Angel' Stephen 'tWitch' Boss' Death (Exclusive)

The former 'Ellen' DJ died by suicide earlier this week.

The cast of Dancing With the Stars is in mourning after learning of Stephen 'tWitch' Boss' death. ET spoke to the show's pro dancers as they rehearsed for the upcoming DWTS tour, and they all expressed disbelief over the tragic loss. Boss, who was married to and shared three kids with former DWTS pro Allison Holker, died by suicide earlier this week. He was 40. 

"I think it's just disbelief," Alan Bersten said. "I think anyone who's ever met tWitch will say that he's the nicest, most caring, most present person, really wants to make everyone feel better. It's so devastating. I didn't believe it."

"When I first started dancing in this entertainment business it was on So You Think You Can Dance. He was the poster child, the pinnacle, the guy that never gave up and just kept going," he continued of Boss, who was a runner-up on the show and later served as a judge. "He made it on the show and became such an inspiration to so many dancers, including myself. It's so hard to believe."

One of the dancers that Boss had a great impact on was Alexis Warr, who won season 17 of So You Think You Can Dance, on which Boss was a judge.

"He was my judge when I did So You Think You Can Dance and he's, like, the reason we stayed sane in a way," she told ET. "He provided so much support and so much guidance to us all. He really made an individual connection with each one of us and just made sure that we were loved and supported. He was like a proud dad to us. We always knew that he had our backs. He really taught us a lot of life lessons on the show, but also just in life in general."

As for her favorite memory of Boss, Warr thought back to the moment after her audition for the competition.

"I remember after my audition, the look in his eyes, I just saw how proud he was. He didn't even have to say anything. I just saw it. I couldn't help but choke up on stage," she said. "He made a comment... 'This is your moment'... He basically gave me the confidence that I needed throughout that season."

Now that Boss is gone, Warr said she feels like there's "a huge chunk of our hearts that's missing."

"I was in complete disbelief and just shock and I feel like I still am. It's just so unimaginable and it's such a tragic thing to happen," she said. "... It's so heartbreaking. I feel almost numb."

Meanwhile, Emma Slater told ET that there aren't "enough good words to say about tWitch, just the positive impact he had on people."

"For me, I was in complete shock and I think just the sheer sadness of how this happened really made people understand worldwide just how fragile life is and to tell each other you love each other and to really check in," she added. "I know he has had definitely a profound impact on me."

"I just thought he was an angel. I really did," she continued. "...I can't believe that something like this has happened to somebody who was just so good and so pure."

Sasha Farber concurred, calling Boss "the nicest guy ever," and noting that the late Ellen DeGeneres Show DJ "would always come and make sure to go out of his way to help someone, to give you information."

"tWitch was such a significant part of the dance community, but then he had this amazing ability to go beyond that," Britt Stewart noted. "He just lit up every room. He was so positive no matter where he was. I know, personally, I really want to send a lot of love and light to his wife, Allison, who I've know since I was a teenager and his kids, of course."

Next, Ezra Sosa revealed that he learned the tragic news from his good friend, JoJo Siwa, who served as a judge on So You Think You Can Dance alongside Boss.

"The day of his passing, I woke up to my friend JoJo calling me. I know every single time she calls me I have to answer 'cause I know it's important," he told ET. "She was hysterically crying. Nothing was coming out, I was just trying to get her to speak, and when I figured out what she was saying... I don't know, it's still hard to process."

"It's still something really hard for us all to process, because he wasn't just close to one of us, we all felt very close and connected to him as well," Sosa added. "It's really hard."

Kateryna Klishyna agreed, admitting that the reality of the situation "just doesn't fit in my head," while Brandon Armstrong spoke about the lessons he hopes people can take away from this tragedy.

"We're just praying for the family, praying for Allison and the kids, and hoping that people can use this as an opportunity to reach out to the people that they love, reach out to the people that may be struggling," he said. "If you are struggling, reach out to the people that love you. Know that you always have a family around you, you always have support."

Ahead of the interviews, a source told ET that the DWTS cast was "confused, and feeling so many emotions while trying to be there for Allison and each other" in the wake of Boss' death.

"They are all texting and calling each other and trying to make sense of this," the source shared. "tWitch was such a genuine and good-hearted person, and his loved ones are feeling his tremendous loss."

The Dancing With the Stars tour will kick off Jan. 6 in National Harbor, Maryland. Visit DWTSTour.com for tickets.

If you or someone you know needs help, please call the National Suicide Prevention Lifeline at 988.