Chadwick Boseman managed to keep his cancer battle private before his death at age 43. But the star did have some rough moments in public, including one that the Tony-Award winning director of Boseman’s last film, Ma Rainey’s Black Bottom, discussed with WSJ. Magazine. George C. Wolfe recalled how one moment seemed to touch a nerve with Boseman.

It came as the trumpet player Levee (Boseman) belittled Cutler (Colman Domingo) for being a man of faith.

“We were doing it in a very casual way, and I assumed that when Levee got to the big speech that Chadwick was going to stop. But he didn’t stop. He kept going, and Levee took over—it was raw and explosive,” remembered Wolfe. “Afterwards, Chadwick just started to sob, and Colman hugged him, and then Chadwick’s girlfriend basically picked him up.”

Boseman was dating Taylor Simone Ledward at the time, but they married before his death in August, four years after being diagnosed with stage 4 colon cancer.

Domingo also recalled how he could see something was happening with Boseman: “I could tell with Chad sometimes, he had something on his mind. He’d walk into a room and he wouldn’t speak to anyone.”

Domingo then jokingly confronted the actor, saying, “Oh, you’re just not going to say hi to anybody?” Domingo recalled Boseman smiling and then making it a point to shake his hand and give him a hug every day on set.

Ma Rainey's Black Bottom starts streaming on Netflix on Dec. 18.