And in even more exciting news, ET has learned she's paired with a fan favorite: Val Chmerkovskiy!
"Val is beyond excited about his partner this season," the source said. "He’s completely re-energized and is feeling really optimistic about this season."
The source adds that Chmerkovskiy is ecstatic and can't stop talking about how excited he is to work with his dance partner. The source says that in regard to his partner, the 31-year-old pro dancer has said, "God is good."
Chmerkovskiy came close to taking home the mirrorball trophy last season with Fifth Harmony star Normani Kordei. Although they were frontrunners from the beginning, #TeamValmani placed third, below second place finishers David Ross and Lindsay Arnold and season 24 champions Rashad Jennings and Emma Slater.
As fans of the popular dance competition know, Chmerkovskiy is known for wowing audiences with his creative, jaw-dropping choreography. This season, he'll have a tremendous story to share through dance, as Arlen's is truly a remarkable one.
The Boston, Massachusetts, native is currently a television personality for ESPN, as well as an actress, speaker and model who has beat the odds.
When she was just 11 years old, Arlen developed two rare conditions known as transverse myelitis and acute disseminated encephalomyelitis. This caused her to quickly lose the ability to speak, eat, walk and move, and was told by doctors that there was little hope for survival and that recovery was highly unlikely.
Flash forward to 2010, and the impossible was made possible when Arlen learned how to speak, eat and move again. Two years later, Arlen qualified for the 2012 Summer Paralympics in London as a paralympic swimmer with Team USA. She won four medals that year: one gold and three silver.
Then, in 2016, she learned how to walk after spending nearly a decade paralyzed from the waist down.
"On this day, April 29, 2006, my life was forever changed," Arlen wrote on Instagram earlier this year, sharing pics of her journey. "I never knew how precious life was until I was perfectly fine one day and in a blink of an eye I was laying in a hospital bed, unable to walk, talk, eat, move and fighting for my life. For four years unbeknownst to my loved ones I was trapped in a vegetative state literally 'locked in' my own body. Constantly hearing doctors tell my family that it was highly unlikely that I would survive and if I did survive I'd be a vegetable the rest of my life."
"But, guess what?" she continued. "I had other plans, I wanted to LIVE. It wasn't easy but through a lot of hard work, hope, faith and incredible support from my family and friends. Little by little I came back to life and not only survived but thrived."
Arlen and Chmerkovskiy will be competing against Property Brothers star Drew Scott and Emma Slater, who were the first pair to officially be announced on Good Morning America.
The rest of the season 25 cast will be revealed on GMA on Sept. 6, but ET has already learned that Nikki Bella and Vanessa and Nick Lachey are three of the other contenders. ET has reached out to ABC for comment, but the network doesn't comment on casting rumors ahead of their official announcement.