As word of Sassoon's death spread on Twitter, so too did idiocy.
"I didn't know Vidal Sassoon (RIP) was a real person, i thought the companies Vidal and Sassoon had merged once years ago," tweeted Chris Davies, a web developer from Birmingham, England.
"Vidal Sassoon was a real person? I honestly didn't know. I thought it was just a brand name. RIP dude. Thanks for the shampoo, or something," said James Hoffer, a self-described total music nerd from Virginia.
"Slightly embarrassed that I did not think Vidal Sassoon was a realperson. Kinda like J. Crew," tweeted @rebelpol, a writer, political geek, outdoor photographer and southern daughter from Jackson, Miss.
Karen Tumulty, national political correspondent for the Washington Post, wondered whether those who believed Vidal Sassoon wasn't real had other head-scratching false beliefs.
"How much overlap is there between people who didn't know vidal sassoon was a real person, and ones who thought the Titanic was just a movie?" Tumulty tweeted.
Sassoon revealed he had blood cancer in 2011, although he was first diagnosed with leukemia in 2009.
His legacy is more than just about the hair products that we use every day or his eponymous salons.
"Mr. Sassoon brought a kind of architectural design to the haircut in the late 1950s and early 1960s, developing a look that eschewed the tradition of stiff, sprayed styles with the hair piled high and that dispensed with the need for women to wear hair curlers to bed and make weekly trips to the salon," the New York Times wrote in its obituary of Sassoon.
Sassoon described his technique in a 1999 profile in the Los Angeles Times.
"When I first came into hair, women were coming in and you'd place a hat on their hair and you'd dress their hair around it," Sassoon told the paper. "We learned to put discipline in the haircuts by using actual geometry, actual architectural shapes and bone structure. The cut had to be perfect and layered beautifully, so that when a woman shook it, it just fell back in."
If you never want to sound foolish again, here are other brand names or characters that are in fact real people:
Colonel Sanders: His face adorns every Kentucky Fried Chicken joint - and that face is real. Harland David Colonel Sanders founded the successful fast food franchise that became Kentucky Fried Chicken. He was given the nickname Colonel by then-Kentucky Gov. Ruby Laffoon in 1935. Sanders died in 1980. You can read his New York Times obituary here.
Johnnie Walker: Whether you love him in red, black, green, gold or blue, Johnnie Walker is real. John Walker was born in 1805 in Kilmarnock, Scotland and started selling his own whiskies in 1825. Although Walker died in 1857, his son Alexander took over the family business, which included their own whisky, and began selling it worldwide. Learn more about Johnnie Walker here (must be 18 or over to access website).
Little Debbie: The blue-eyed girl that's the face of the snack cakes is the face of an actual person. Little Debbie is the granddaughter of O.D. McKee, who named his brand of snack cakes after Debbie. His inspiration? A photo of Debbie in play clothes and her favorite straw hat, according to this Little Debbie brand history.
Chef Boyardee: Chef Boyardee's cans of ravioli and other pastas were the brainchild of real life chef Ettore Hector Boiardi. Boiardi changed the spelling of his name when he launched his products so Americans could easily pronounce his name. Boiardi did in 1985 of natural causes. More info on Boiardi can be found here.
Sara Lee: This rival to the fake-named Betty Crocker line of baked goods is a real person. It was Sara Lee's father, baker Charlie Lubin, who decided to name the brand after her. "Although the real Sara Lee has never had a management role at the corporation, she has appeared in some television advertisements for our bakery products," the Sara Lee website says. "In her words, her father told her the product 'had to be perfect because he was naming it after me.'"