A bodybuilding champion and influencer has died suddenly at the age of 31 — just weeks after proposing to his girlfriend on stage.

Ricardo Nolasco dos Santos, known in the bodybuilding world as Kadu Santos, died in Novo Hamburgo in southern Brazil on Monday. His cause of death has not yet been made public, according to the Sun.

“The saddest day of my life. My beloved son,” his heartbroken father, Amauri Santos, wrote on social media, confirming his son’s death.

Santos, an 11-time bodybuilding champion and a two-time overall champion of the prestigious Muscle Contest, had just become engaged to personal trainer Sabrina Wollman on stage at an event in July.

They had been dating exactly four years to the day he proposed.

“I love you with all my heart, I admire you and I’m very proud of who we’ve become together over the years,” Wollman wrote in an Instagram post showing Santos asking her to marry him.

“Thank you for always making me the best version of myself. I choose you every day to share this crazy life with!” she wrote.

Santos also worked as a personal trainer and offered consulting online, where he frequently shared his rigorous workouts and competitions with his 13,000-plus followers.

Fellow bodybuilder Diego Wiegand said in a heartfelt tribute that “Heaven is definitely partying today.”

“It is with a heavy heart that I say goodbye to you today,” he continued. “You left a legacy here on Earth and will always be remembered by all for the man you were!”

Joel Rodridguez, an event promoter and pal of Santos, said the bodybuilder began training when he was 17 years old with dreams of becoming a champion, NewsX reported.

“He fought hard for this to happen. And he was loved by everyone. A very charismatic, friendly person,” adding that the sport had lost “an athlete with a lot of potential.”

The training center where he worked, PowerCT, mourned Santos in a post describing the athlete as “an example of dedication, discipline and companionship.”