Behind-the-scenes of classic films: Inside Debbie Reynolds' contentious relationship with Gene Kelly

Their on-screen chemistry became iconic in film history, but filming "Singin' in the Rain" was anything but blissful for Gene Kelly and Debbie Reynolds.

The two actors have both since passed, but in the decades following their hit 1952 movie, both Kelly and Reynolds opened up about a working relationship spotted with tears, blood and an alleged sexual advance that forever stuck with Reynolds.

"I had just turned 19 when filming started ... Gene was 37," Reynolds said in 2013. "He never wanted me in 'Singin' In The Rain.' When studio chief Louis B Mayer told him I was going to be his leading lady, Gene stared at me and said, 'What have you done before?'"

Despite Kelly's apparent resistance, the studio had made its decision. But that didn't mean Kelly, who directed the film while also starring in it, would soften: "My feet were bleeding from all that dancing and when I pointed it out, Gene would say, 'Clean it up,'" Reynolds recalled. "He was very sentimental like that."

It wasn't just the technical stunts that drew Kelly's ire, she said. "If I wasn't smiling, Gene would yell at me to smile more. During filming I thought my cheeks were going to crack from all that smiling."

In her 2013 memoir, "Unsinkable," Reynolds described the moment she and Kelly filmed their characters' first kiss -- a kiss she expected to be chaste, as was typical in films of that era.

"The camera closed in. Gene took me tightly in his arms . . . and shoved his tongue down my throat," Reynolds wrote. 'Eeew! What was that?' I screeched, breaking free of his grasp and spitting. I ran around frantic, yelling for some Coca-Cola to cleanse my mouth. It was the early 1950s, and I was an innocent kid who had never been French-kissed."

She continued, "It felt like an assault. I was stunned that this thirty-nine-year-old man would do this to me."

Kelly died in 1996, years before Reynolds' memoir would be penned. But in the years before his death, he reportedly did once say, "I wasn't very nice to Debbie. I'm surprised she still speaks to me."

Kelly's widow, Patricia Kelly, countered some of Reynolds' assertions before they were detailed in her memoir. In 2012, when asked about her husband's attitude toward Reynolds, she said he was only hard on her with the intent of creating a great movie.

"You want your partner to look the best he or she can possibly look," she said. "And that was always his intent with Debbie, and she worked like a trouper and became a big star."

And while Reynolds stood by her memories of what transpired on set, she didn't hold a grudge against Kelly: "He was a hard taskmaster but he was also brilliant and he taught me a lot."