The Hollywood veteran helped her banish the insecurities that had blighted her during her early career.
Writing for Darling Magazine, Megan said she was, "Trying to find my value in an industry that judges you on everything that you're not versus everything that you are.
Other executives deemed her, "Not thin enough, not pretty enough, not ethnic enough, while also being too thin, too ethnic, too pretty the very next day", Meghan wrote.
Still in her early 20s, she was struggling to come to terms how she was being viewed and the fickleness of Hollywood, and its obsession with image.
But she said her approach to finding worked changed in an instant after an encounter with Webster that allowed her to stop hiding behind materialism and be herself.
Meghan wrote: "I had never met her before, and at my very first audition for her, she stopped me mid-scene and said so simply, 'You need to know that you're enough'."
"I was breathless. No one had ever seen it, or perhaps no one had ever called me out, but there in that small box of a room in Burbank, this woman I had never met saw me.
"My gut reaction was to smile. To smile hard. Maybe that would keep the tears tucked behind my draping eyes.
"It wouldn't have mattered if I cried, because she saw me. She saw all that self-doubt beaming through the self-tanner and excessive blush.
'"You need to know that you're enough," she said.
"'Less makeup, more Meghan'".
"She went on to say that I was like a 'shrinking violet,' wilted joy and energy and exuberance behind this shroud of insecurity. You couldn't pay for a therapy session this good.
"And that moment, for me, was a wake-up call."
Her determination to make it was evident in home video footage that emerged this week of an 18-year-old Meghan before and after an audition for a Shakira music video.
Shot in the summer of 1999 when she was 18, she is brimming with excitement at the $600 - she stands to earn from the shoot.
The humble Volvo hatchback she drives in the clip is a far cry from her present-day surroundings - having grown into successful TV star and become engaged to Prince Harry during the intervening two decades.