Researchers at MyHeritage have linked Sydney Sweeney and Marilyn Monroe as ninth cousins once removed, Entertainment Weekly reported Oct. 7.
The relationship runs through Sweeney’s father, Steven Sweeney, and Monroe’s biological father, Charles Stanley Gifford.
Roi Mandel, MyHeritage’s director of research, said the public comparisons between the actresses prompted his team to search for “a real bond in the MyHeritage archives.”
Entertainment Weekly said it could not reach Sweeney for comment.
A Massachusetts Settler Connects Their Family Trees
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The two lines converge on Ezra Perry, an early settler in Sandwich, Massachusetts, who lived from approximately 1625 to 1689, according to MyHeritage’s family tree, reproduced by Parade.
Historical research preserved by the Sandwich Historical Commission identifies Perry’s first recorded appearance in America in a town record from 1644. He pledged nine shillings toward repairs to the community’s meetinghouse.
He later served in the militia and was appointed constable in 1679. His will, dated the day he died, bequeathed livestock, household furnishings and other possessions to his wife and children.
The cousin designation places a common ancestor at the level of an eighth-great-grandparent for one person and a ninth-great-grandparent for the other. “Once removed” describes that difference of one generation in their descent, using the relationship calculation explained by FamilySearch.
Monroe’s Father Was the Subject of a DNA Investigation
The 2022 documentary Marilyn, Her Final Secret investigated Monroe’s paternity using a preserved lock of her hair and DNA from Gifford’s family. Producer Label News described the 52-minute film as the result of more than two years of investigation.
John Reznikoff, president of University Archives in Connecticut, told Inside Edition that the hair used in the testing had come from Monroe’s embalmer. Filmmaker François Pomès told the program he was “100%” sure of the identification.
Gifford had an affair with Monroe’s mother, Gladys, in 1925. Inside Edition reported that testing identified a familial DNA match involving his granddaughter, Francine Gifford Deir, who described Monroe as her aunt.
Sweeney’s Vintage Gown Recalled Monroe’s First LIFE Cover
At the Santa Barbara International Film Festival on Feb. 8, Sweeney wore a cream Ceil Chapman gown nearly identical to Monroe’s dress from her first LIFE cover, PEOPLE reported.
Sourced from vintage retailer Timeless Vixen, the gown featured an off-the-shoulder neckline, a round brooch at its center and ruching through the waist. Sweeney’s stylist, Molly Dickson, confirmed the reference to the late actress.
Monroe’s cover appeared on April 7, 1952, with a photograph by Philippe Halsman, according to the LIFE archive. She appeared on the magazine’s cover six times during her lifetime.
Chapman launched her own label in 1940 and dressed Hollywood clients including Elizabeth Taylor and Deborah Kerr as well as Monroe. The ASU FIDM Museum credits her with elaborate draped bodices and patented draping techniques, along with dramatic necklines and silhouettes that emphasized the hips.
Sweeney was receiving the festival’s Virtuosos Award for her performance in Christy. The honor recognizes breakthrough screen performances, and the ceremony took place at the Arlington Theatre.
Her Housemaid Premiere Dress Was Custom Made
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For the Los Angeles premiere of The Housemaid on Dec. 15, 2025, Sweeney chose a custom white halter gown that recalled Monroe’s costume in The Seven Year Itch. She arrived at the TCL Chinese Theatre with loose blonde waves and red lipstick, PEOPLE reported.
Galia Lahav head designer Sharon Sever developed the look with Dickson and Sweeney, combining a sculpted, corseted bodice with an elongated skirt edged entirely in feathers.
The fashion house said the gown required more than 170 hours of handwork, with fabrics selected to give it both structure and movement. It was Sweeney’s second custom creation from the label, following the dress she wore to Jeff Bezos and Lauren Sánchez’s “Dolce Notte” celebration in Venice.