Martha Stewart's whole life crumbled in 2004. Her best friend played a part in her downfall.

In 2004, Martha Stewart, an icon of American lifestyle and homemaking, saw her entire empire unravel in a highly publicised insider trading trial.

But the twist that added salt to the wound? Stewart's long-time best friend, Mariana Pasternak, took the stand against her, delivering testimony that would help lead to Stewart's conviction and subsequent prison sentence.

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Their friendship, once full of shared life experiences and mutual support, ended in the most dramatic way possible — in a courtroom.

Stewart and Pasternak had been close for over 20 years. The two met in Westport, Connecticut, in the 1980s and quickly became inseparable.

Stewart even served as the maid of honour at Pasternak's wedding and was godmother to her children. Together, they shared countless holidays and milestones, with Pasternak becoming a fixture in Stewart's life.

Image: Good Morning America

From morning phone calls to family holidays and travel expeditions that fuelled Stewart's media empire, the pair were rarely apart.

Their friendship extended into Stewart's burgeoning career. Pasternak often featured in Stewart's famous TV specials, and her family became part of Stewart's world of lifestyle programming.

The duo travelled to locations like the Galapagos, Egypt, and the French Riviera, scouring the globe for new ideas to enrich Stewart's brand.

Image: Good Morning America

As Pasternak would later recount, Stewart was someone who "needed company" constantly and could become "unpleasant" when left alone, saying, "She gets very edgy and can get very unpleasant. Yet the company must always be engaging."

Stewart's magnetic personality, high standards, and drive made her successful, but also difficult — and Pasternak seemed to thrive in the role of confidante and companion.

The bond wasn't without its tensions. According to Pasternak, Stewart could be controlling, even competitive.

Image: Good Morning America

Pasternak recalls in her memoir The Best of Friends: Martha and Me, that Stewart would sometimes go so far as to mimic her personal style. "What I tried on, she tried on," Pasternak writes, hinting at a dynamic in which Stewart seemed to rely on Pasternak's companionship, yet overshadowed her in many ways.

As Pasternak described it, she enjoyed the protection and status that came with being in Stewart's inner circle, but their friendship had long-standing cracks beneath the surface.

The ultimate fracture, however, came with the infamous ImClone scandal.

In December 2001, Stewart sold her shares in the pharmaceutical company ImClone just before the stock plummeted, prompting federal investigators to suspect she had engaged in insider trading.

During the trial, it was Pasternak's testimony that delivered a decisive blow.

Image: Getty

Recounting a holiday she and Stewart had taken around the time of the stock sale, Pasternak claimed that Stewart had said, "Isn't it nice to have brokers who tell you those things?"

The comment hinted that Stewart may have had prior knowledge about the stock's likely downturn — a critical piece of evidence in the case.

Though Pasternak later admitted uncertainty, saying she wasn't entirely sure Stewart had made that comment or if it was a "thought" in her mind, the damage was done.

Stewart was ultimately convicted of obstruction of justice and making false statements, leading to a five-month prison sentence.

The moment Pasternak took the stand was, according to both women, the end of their friendship. Stewart, watching from across the courtroom, would later say she knew then that their relationship was over.

Pasternak herself felt the impact: "I said that Martha said it, and I looked and I saw Martha's face and her eyes became cold," she would recall.

Martha later said of the life-changing moment, "I knew when I saw her [Pasternak's] face across the courtroom that our friendship was over."

Image: Good Morning America.

After the trial, Pasternak faced backlash from Stewart's supporters, and she struggled to maintain her career and reputation. She later chronicled her version of events in her 2011 memoir, The Best of Friends: Martha and Me, where she recounted the highs of their friendship as well as the painful end.

"I had grown tired of being a participant in Martha's life," Pasternak writes, describing how the friendship's rewards felt "less satisfying" over time.

Despite this, she admits she wish she had spoken to her former best friend following the trial, saying, "I wish she would have called me after the trial when so many things happened, and I [was] put through so much stress, to tell me, 'I so regret that I involved you in my mess and you had to go through all of this.'"

Pasternak's account also casts Stewart in a more complex light. Though she paints her friend as brilliant and daring, she doesn't shy away from describing Stewart's darker traits – her competitiveness, her high standards, and the toll these took on those around her.

According to Pasternak, Stewart's friendships were often intense and possessive, with Stewart expecting undivided loyalty from those close to her.

Today, Stewart has moved on from the scandal, rebuilding her brand and even gaining a new generation of fans through surprising collaborations, like her partnership with Snoop Dogg, who Stewart calls her new "best friend."

"Snoop is now my best friend. We're besties, we're homies," Martha once gushed about the rapper.

Image: Getty.

In 2010, during an appearance on Good Morning America to promote her book about her friendship with Stewart, Pasternak was asked what she would say to her former friend if given the chance.

"I would tell her how happy I am that she's back on TV she's back everywhere, I know she loves that and I know it's important to Martha. I hope she is happy for me that I want to get my life back," she said.

Feature Image: Martha Stewart.