If we define "worst" as "most expensive," we can get some pretty clear answers:

• Mel Gibson and Robyn Denise Moore - The couple met in the late 1970s and married June 7, 1980, then filed for divorce in April 2009. When the divorce was finalized in 2011, Moore was reportedly awarded half of Gibson's $850 million fortune.
• Michael Jordan and Juanita Vanoy - The couple married in September 1989 in Las Vegas and filed for divorce on Dec. 29, 2006. Vanoy was awarded $168 million in the settlement, along with the couple’s seven-acre Chicago estate and custody of their three children.
• Neil Diamond and Marcia Murphey - The couple was married for 26 years, and many sources reported that Diamond gave up $150 million in his divorce settlement with Murphey. However, the singer claimed the reports were inaccurate.
  "It wasn’t true," he told The Daily Mail, though also adding that "[Murphey] got enough to live on for the rest of her life."
• Harrison Ford and Melissa Mathison - Per The Telegraph, Ford paid Mathison somewhere between $85 million and $90 million when they divorced in 2004. Mathison was a Hollywood success story in her own right, as she was a working screenwriter with credits including E.T. the Extra-Terrestrial.
  Mathison also reportedly received a percentage of Ford's royalties from movies he’d made during their marriage, which included films in the Star Wars and Indiana Jones franchises.

However, you didn’t ask about the "most expensive" celebrity divorces, so let’s assume that you want some of the stories that captured tabloid headlines. Here are a few of the most famous:

• Jennifer Aniston and Brad Pitt - Pitt met Aniston in 1998 when their agents set them up; while the Hollywood mega-stars tried to keep their relationship under wraps at first, tabloid rumors swirled, and they went public by appearing on the red carpet at the Emmy Awards in 1999. They married on July 29, 2000.
  By 2004, Aniston spoke about wanting to slow down and start a family. Around that time, however, Pitt began working alongside Angelina Jolie in Mr. and Mrs. Smith. In an interview with Vogue, Jolie explained how their relationship developed.
  "Whether it was shooting a scene or arguing about a scene or gun practice or dance class or doing stunts—anything we had to do with each other, we just found a lot of joy in it together and a lot of real teamwork," she said. "We just became kind of a pair. And it took until, really, the end of the shoot for us, I think, to realize that it might mean something more than we’d earlier allowed ourselves to believe."
  Tabloids ran stories about Pitt’s alleged infidelity. The Pitt-Aniston marriage ended in October 2005, and the couple released a joint statement noting that the decision was "not the result of any of the speculation reported by the tabloid media."
  In later interviews, however, Aniston admitted that she was hurt by the rumors.
  "There was stuff printed there that was definitely from a time when I was unaware that it was happening," she said. "I felt those details were a little inappropriate to discuss. That stuff about how she couldn't wait to get to work every day? That was really uncool."
• Wendy Williams and Kevin Hunter - The talk show host married Hunter in November 1997. Soon after, Hunter became heavily involved in Williams' business life, becoming her manager, agent, and eventually an executive producer on The Wendy Williams Show.
  Behind the scenes, the couple reportedly dealt with numerous issues; they had a son in 2000, but Hunter reportedly cheated on Williams shortly afterward.
  Williams wrote about the situation in her 2003 memoir, but in recent years, the scale of the story has expanded considerably. Hunter allegedly lived a double life, purchasing a home for his mistress a few miles from his home with Williams. He allegedly fathered a child with his other lover. Williams filed for divorce in April 2019.
• Tiger Woods and Elin Nordegren - As one of the most shocking and high-profile divorces in recent memory, Woods' divorce with Elin Nordegren certainly deserves a spot on this list.
  Married October 2004. Divorced August 2010. They had their first child in 2007, followed by a second in 2009. A few days before Thanksgiving in 2009, Nordegren first heard rumors of Woods' infidelity with Rachel Uchitel. Woods denied the allegations, but Nordegren allegedly checked his phone and found evidence.
  Woods left the house and crashed his car into a fire hydrant. Over the next few months, 15 other women came forward to say that they’d had affairs with Woods.
  "I never suspected, not a one," Nordegren said shortly after the divorce was finalized. "For the last three-and-a-half years, when all this was going on, I was home a lot more with pregnancies, then the children and my school."
  While she stated that she’d "been through hell" and that she was "blindsided" and "embarrassed" by the affairs, she wished her ex-husband well.
  "I know he is going to go down as the best golfer that ever lived, and rightfully so," she said. "I feel privileged to have witnessed a part of his golfing career."
  The couple had a prenuptial agreement, and Nordegren reportedly walked away from the marriage with close to $100 million.
• Nicole Kidman and Tom Cruise - When they married in December 1990, Nicole Kidman and Tom Cruise seemed like the perfect Hollywood power couple, and while we don’t know many details about their divorce, they certainly captured tabloid headlines.
  They split in August 2001, and while both stars refrained from commenting on the details, some sources (including Scientology whistle-blower Leah Remini) suggested that Cruise’s commitment to Scientology drove a wedge in the marriage.
  Cruise gained custody of their two children, Bella and Connor, who are practicing Scientologists. Later, when Remini asked them about their mom, Bella replied, "Our mom is a f***ing SP." In the Scientology community, SP is short for "suppressive person."
  In an interview with Who magazine, Kidman commented on her relationship with Bella and Connor.
  "They are adults," she said. "They are able to make their own decisions. They have made choices to be Scientologists, and as a mother, it’s my job to love them."
  Kidman has spoken about the marriage in several interviews, but she typically refrains from giving too many details.
  "I became famous very young," she said. "I became very famous because I was the wife of somebody. I felt I became a star only by association. I didn't think (my early movies) were very good, which is why I would always cower in the background. I thought, I don't deserve to be here. We would go to the Oscars and I would think, I'm here to support him. I felt it was my job to put on a beautiful dress and to be seen and not heard."
• Russell Brand and Katy Perry - The couple met in mid-2009 while filming Get Him to the Greek, then began dating after meeting again at that year’s VMA Awards. They married in October 2010. Within a year, they had split, and they were seen vacationing (separately) without their wedding rings. Brand filed for divorce in December 2011, allegedly asking for the legal separation via text message.
  "We did work it out, she’s happy, I’m happy," he said of the divorce in an interview with Howard Stern. "I was really, really in love with her, but it was difficult to see each other, it mostly didn't work for practical reasons."
  But in a documentary filmed during the couple’s marriage, Brand slammed Perry’s lifestyle and mocked their relationship.
  "I'm associated with the very thing I detest: vapid, vacuous, plastic, constructed, mindless celebrity," he said. "That's the very sea we're swimming in, 'Oh, who's he?' ... 'He's married to Katy Perry.'"
  "This is my suspicion, that at some point, to be happy, I'm going to have to walk away," he told a friend in the same documentary.

Celebrities have a higher divorce rate than the general population, and unlike the rest of us, they're often forced to deal with tabloid headlines, paparazzi, and internet rumors, so it's no surprise that some have issues ending their marriages on a high note. We should note that some rumors aren't true, so take the above stories (and the divorce financial figures) with a grain of salt.