The actress began dating the Los Angeles-based photographer in October 2015.
LOS ANGELES -- Sandra Bullock's partner Bryan Randall has died.
A rep for the actress confirmed to ABC News that Randall died Saturday following a three-year battle with ALS, or amyotrophic lateral sclerosis.
"Bryan chose to keep his journey with ALS private and those of us who cared for him did our best to honor his request," Randall's family said in a statement. "We are immensely grateful to the tireless doctors who navigated the landscape of this illness with us and to the astounding nurses who became our roommates, often sacrificing their own families to be with ours."
"At this time we ask for privacy to grieve and to come to terms with the impossibility of saying goodbye to Bryan," they added.
Bullock's sister Gesine Bullock-Prado, shared a tribute to Randall on Instagram on Monday, in which she said she is "convinced that Bry has found the best fishing spot in heaven and is already casting his lure into rushing rivers [tee]ming with salmon."
Bullock-Prado also praised her "amazing sister and the band of nurses she assembled who helped her look after [Randall] in their home" as he battled ALS, which she called "a cruel disease."
"Rest in peace, Bryan," she added.
ALS is a progressive neurodegenerative disease that affects nerve cells in the brain and spinal cord, according to the ALS Association. The initial symptoms of the disease can be varied and can include trouble grasping a pen or lifting a coffee cup, while some may experience a vocal pitch when speaking, the ALS Association says.
The National Institute of Neurological Disorders and Stroke says that ALS has no cure and there is no effective treatment to reverse its progression.
Over the years, Bullock has kept her relationship with Randall private.
According to People, Bullock met Randall in January 2015. They made their red carpet debut in October 2015 at the "Our Brand is Crisis" premiere in Los Angeles.
The two were also photographed together at the "Oceans 8" world premiere in June 2018 in New York City.
In an interview with Jada Pinkett Smith, Adrienne Banfield-Norris and Willow Smith on "Red Table Talk" in 2021, the "Miss Congeniality" star opened up about her relationship with Randall.
"I am someone who went through the divorce process," she said. "I found the love of my life. We share two beautiful children -- three children, his older daughter. It's the best thing ever."