Beyoncé's dad is battling breast cancer.
Mathew Knowles shared the startling news in a teaser for "Good Morning America" on Tuesday, ahead of his sit-down interview which will air tomorrow.
Taking a seat with Michael Strahan, the 67-year-old reveals his diagnosis for the first time to the world.
In the short clip, the "GMA" host is heard asking Beyoncé and Solange's father about breaking the news to his famous daughters.
"How was it to tell your family about the diagnosis?" Strahan asks.
Mathew Knowles is best known for managing Destiny's Child during their career, but has been out of the public eye after Beyoncé cut ties with him professionally when she went solo.
Their personal life took a hit too, with his Grammy winning daughter suing him over the rights to the Destiny's Child brand.
Mathew and their mom, Tina, split in 2009 after it was revealed he had fathered a child with another woman.
The duo were married for 31 years total. In 2013, he remarried and neither Beyoncé nor her sister Solange attended the wedding.
Mathew has attempted to repair his relationship with his daughters and has even met his grandchildren.
Beyoncé has three kids -- Blue Ivy, 7, and 2-year-old twins Rumi and Sir. Mathew's oldest grandchild is Solange's son, Daniel Julez Smith Jr., who's 14.
Beyoncé and Solange's brother is now 9 years old and bares their famous name.
Beyoncé shared a rare photo with her two parents last year at the end of her "On the Run II" tour.
Posing with Tina and Mathew kissing both sets of cheeks, Queen Bey looked happy to have her parents supporting her.