'Being the Ricardos' fact check: Was Lucille Ball a communist? And why couldn't she say 'pregnant' on TV?

Spoiler alert! This story contains major plot details about "Being the Ricardos" (now streaming on Amazon Prime). 

Aaron Sorkin, you've got some ’splaining to do. 

The writer/director's new drama, "Being the Ricardos" (now streaming on Amazon Prime ), imagines a tumultuous week of production of the hit 1950s sitcom "I Love Lucy," as husband-and-wife duo Lucille Ball (Nicole Kidman) and Desi Arnaz (Javier Bardem) fend off accusations of infidelity and communist support, and break the news that Ball is pregnant to strait-laced network executives. 

"Everything that happens in the movie happened – it just didn't all happen in the same week," Sorkin says. The filmmaker breaks down some of the awards contender's biggest moments and the real-life history behind them.

'Being the Ricardos':Nicole Kidman's husband, kids helped her prep to play Lucille Ball

Was Lucille Ball actually a communist? 

In 1953, it was revealed that Ball had registered to vote as a member of the Communist Party on a voter registration application from 1936. As shown in the film, she said she only did it to pacify her dying socialist grandfather and denied any active involvement in the party. (A screenwriter testified that she hosted a Communist Party membership meeting at her house in 1937, but she wasn't there.) 

At the time of the Red Scare, with other Hollywood actors, directors and screenwriters getting blacklisted, even the slightest ties to communism could've been catastrophic for Ball. 

"She's getting nailed for something she did years ago that didn't amount to any more than checking a box, and now she's gonna be canceled," Sorkin says. " 'I Love Lucy,' the biggest hit imaginable, is gonna have the plug pulled. Her career will be over, Desi's career will be over. It just reminded me a little too much of today." 

In the movie's climax, Arnaz attempts to squelch the controversy at a taping of "Lucy," where he tells the crowd that the only thing "red" about Ball is her hair. He then calls up FBI chief J. Edgar Hoover, who maintains Ball's innocence in front of the studio audience. 

"That's exactly what happened," Sorkin says. "If I had a Ouija board, I'd get Desi Arnaz on the phone and ask, 'What did you have on Hoover that got him on the phone like that?' " 

Did Lucille and Vivian really not get along? 

In one scene, Ball and co-star Vivian Vance (Nina Arianda) have a heated confrontation after Ball secretly sends breakfast to her dressing room, in an underhanded effort to keep Vance heavier than herself. "Vivian was a sexy, glamorous ingenue who had to play the frumpy downstairs landlady (Ethel), and as we see in the film, that caused tension between these two best friends," Sorkin says. "Vivian felt, 'Lucy's doing this to me so she will be the more attractive one.' " 

In a 1975 reunion, Vance, sitting next to Ball, shared a mock “contract” Ball drafted up during their “Lucy” days, joking that Vance “must also agree to put on an additional five pounds every month for the next year.” 

Was there actually network pushback to her pregnancy? 

It's true that when Ball got pregnant with her second child, Desi Arnaz Jr., during the production of the sitcom's second season, CBS executives immediately ordered that she conceal her baby bump on TV by hiding behind sofas, boxes and other objects. Because Lucy and Ricky slept in separate beds on the show, the fear was that audiences would now see the characters as sexual beings. 

Showing a pregnant actress on a major TV show "had never been done before," Sorkin says. "(Execs) were scared of it. It's advertiser-supported television and it was racy." 

Ball and Arnaz fought back and eventually won out, writing a pregnancy storyline for Lucy to coincide with Ball's real-life expectancy. The catch was that they couldn't say the word "pregnant" on TV because it was considered too suggestive, so they settled for "expecting" instead.

The actress gave birth to her son on Jan. 19, 1953 – coincidentally, the same day that "Lucy Goes to the Hospital" aired. The Season 2 episode, in which Lucy gives birth, drew 44 million viewers (nearly 72% of the U.S. population with TV sets).

Did Lucille really learn about Desi's infidelity in a tabloid? 

"Ricardos" opens with Ball confronting Arnaz over a story in Confidential magazine, which pictures him with another woman and reports that he's cheating on his wife. In reality, Ball did square off with Arnaz over cheating allegations on the set of "I Love Lucy" – going so far as to throw a copy of the tabloid to her husband, saying, "I could tell them worse than that,” according to an account her publicist told People. 

"In the film, it's written as Lucy confronting for the first time that Desi might've been unfaithful," Sorkin says. "The truth is, it was an ongoing thing."In their early years, "Desi was away on the road all the time playing with his orchestra and Lucy understood who her husband was. She hated it but she was in love with him." 

That was part of the reason that she fought CBS execs for Arnaz to play her husband in "I Love Lucy," making them one of the first interracial couples to appear on TV. 

"The reason why she agreed to do 'I Love Lucy' was to save her own marriage and get Desi off the road," Sorkin says. "As she says in the film, 'The construction department will build us a little apartment for the Ricardos. That's where we're going to live.' When you're working on a television series 12 hours, five days a week, that is where they spend most of the time." 

Was she truly the brain behind 'I Love Lucy?' 

Some of the drama's most riveting scenes are watching Kidman’s Ball craft jokes and choreograph comedy sequences on the spot.

She was also savvy behind the scenes. Working alongside Ball on "Here's Lucy," Joan Rivers recalled to People a time "when she stopped the shot and said, 'The camera angle is three inches off.' They said, 'Oh, no, Lucy, it’s not.' And she said, 'Measure.' It was."

Reading Arnaz's autobiography, "A Book," "it became plain to me that Lucy was always the smartest and funniest person in the room," Sorkin says. "She was a comedic chess master looking 12 moves ahead. In the writer's room or at rehearsal, she could quickly see whether something was going to work in front of an audience and what had to change."