Sydney Sweeney Is Related to Marilyn Monroe

Sydney Sweeney really is the modern-day version of Marilyn Monroe ... because, as it turns out, the two blonde bombshells are related!!!

Lots of folks have been saying Sydney is the second coming of Marilyn ... from her bombshell looks to her old Hollywood styling and her famous boyfriends ... and the comparisons are getting backed up by blood.

Sydney and Marilyn are ninth cousins, once removed ... according to a new study conducted by MyHeritage.

It's fascinating ... Sydney and Marilyn's family trees actually connect through a shared ancestor from the 1600s.

Sydney's father, Steven Sweeney, and Marilyn's father, Charles Stanley Gifford, are both descendants of Ezra Perry ... an early settler in Sandwich, Massachusetts who died in 1689.

Sydney and Marilyn aren't the only famous relatives discovered by MyHeritage ... they previously determined that "Friends" co-stars Matthew Perry and Courteney Cox were distant cousins too.