No. Notice how their surnames differ. Kaitlin's last name is OLSON while Mary-Kate and Ashley got OLSEN.
Known for her role as Deandra "Sweet Dee" Reynolds on It's Always Sunny in Philadelphia, Kaitlin Olson was born on August 18, 1975 in Portland, Oregon.
Olson’s father, Donald, graduated from the UO School of Journalism and Communication and worked as the publisher of the Portland Tribune. Her mother, Melinda, is the founder of Earth Mama Angel Baby, selling organic, natural herbal pregnancy and baby care products.
The Olsen twins were born in the San Fernando Valley, California on June 13, 1986. Ashley was born first and is technically 2 minutes older than her fraternal twin Mary-Kate. The girls' mother, Jarnette Olsen, is responsible for starting their careers.
Known relatives of Olsen twins primarily include sisters Elizabeth and Taylor and brothers Trent and Jake.
Check out BuzzFeed's list of 17 Celebrities You Had No Idea Were Actually Related To Each Other.
And can you guess which celebrity claims to be related to Kate Middleton? Find out at HelloMagazine.com.