Sydney Sweeney and Marilyn Monroe Are Ninth Cousins, Research Finds
Sydney Sweeney and Marilyn Monroe are ninth cousins, once removed, according to new family-tree research by MyHeritage. The company traced both women to a mutual ancestor, Ezra Perry (c. 1625–1689), The Hollywood Reporter reported on 7 October 2026.
Perry was an early English settler in Sandwich, Massachusetts, a coastal town settled in the first decades of colonial New England. The Hollywood Reporter identifies him as the link that joins the two actors across more than three centuries.
That distance needs a little decoding. Ninth cousins share an ancestor ten generations back up the tree. The phrase once removed simply means the two cousins belong to different generations, in this case separated by one step.
Both lines run through the actors' fathers. Sweeney and Monroe descend from Perry through their paternal lines, according to Consequence, a detail also noted by InStyle. In family-tree language, that means the chain moves from father to father at each step rather than mixing maternal and paternal links.
The study was conducted by MyHeritage, the family-history platform, The Hollywood Reporter said. Inside the company, the work falls to Roi Mandel, its director of research, who oversees celebrity genealogy projects of this kind.
Monroe is not only linked to Sweeney. Actor Dakota Johnson is Monroe's ninth cousin, three times removed, according to the same MyHeritage research. That wording points to the same degree of cousinhood, but with a wider generational gap of three steps.
Ties of this kind are a familiar product of colonial ancestry. Early families were large, records run deep, and after almost 400 years one 17th-century couple can have a large number of descendants scattered across the country. A ninth-cousin match does not mean a close family bond or a shared childhood. It means two very long branches happen to meet at the same trunk.
What makes this stand out is the echo on screen. Monroe remains Hollywood shorthand for blonde stardom, and Sweeney has built her own high-profile career in that same bright spotlight. Now there is a documented line, however faint, joining the two names.
For fans, this means a fun footnote rather than a family reunion. It is the kind of discovery that genealogy services love to surface, and that Hollywood loves to repeat.
