The most dominant tennis player in the world, who is not the most popular or marketable tennis player in the world, is doing something about her off-court reputation.

Tennis.com is reporting that 20-time Grand Slam champion Serena Williams has made an appearance on an upcoming tennis mockumentary for HBO, in which she shows her comedic talents.

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The show, "7 Days in Hell" will air during finals week of Wimbledon on HBO, according to tennis.com. The mockumentary features Andy Samberg and Kit Harrison as the subjects of an elongated tennis match at Wimbledon that lasts seven days.

Samberg's character, Aaron Williams, plays an adoptive Caucasian brother to Serena and sister, Venus, in the project. Their father Richard makes Williams take up the game.

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"It was a reverse Blind Side," Serena explains in the film's new trailer as shown by tennis.com. "You know, a rich white family gets a black kid and makes him play football. Well, we flipped it. You see, my dad, he took a white kid and made him play tennis."

Other tennis names include John McEnroe and Chris Evert, along with broadcaster Jim Lampley.

Serena will go for her 21st Grand Slam championship - and her third of the year - when Wimbledon starts next week. Williams, already considered by some to be the greatest women's tennis player ever, needs just two victories to tie Steffi Graf for the modern-day record for Grand Slam titles with 22.

Williams' dominance in the game gives her an outside chance of catching Margaret Court, who has the all-time record with 24 Grand Slam victories.

But she lags far behind Maria Sharapova in endorsement earnings; Sharapova owns five career majors.

Williams could be taking a page from LeBron James, who has a co-starring role in the upcoming movie "Trainwreck" with Bill Hader and Amy Schumer. James' play in the NBA Finals and his latest attempt at acting could transform him into a more likable athlete overall.

Serena could be going along the same comedic path, combining her celebrity with her exceptional play to make her more likable to fans and marketers alike.