Annalynne and Angel McCord(01 of34)
Open Image Modal (credit:Getty)
Rafaela, Gisele and Patricia Bundchen(02 of34)
Open Image Modal (credit:Getty)
Kate and Oliver Hudson(03 of34)
Open Image Modal (credit:AP)
Erin and Kendra Andrews(04 of34)
Open Image Modal (credit:Getty)
Amy, Jenny and Joanne McCarthy(05 of34)
Open Image Modal (credit:Getty)
Nikki and Nathan Reed(06 of34)
Open Image Modal (credit:Getty)
Rorrey Fenty, Rihanna's brother(07 of34)
Open Image Modal (credit:Getty)
Sienna and Savannah Miller (08 of34)
Open Image Modal (credit:Getty)
Sandra and Sofia Vergara(09 of34)
Open Image Modal (credit:Getty)
(10 of34)
Open Image ModalEmma and Alex Watson. (credit:AP)
(11 of34)
Open Image ModalJustin and Sebastian Theroux. (credit:FameFlynet)
(12 of34)
Open Image ModalMiley and Brandi Cyrus. (credit:Getty)
(13 of34)
Open Image ModalJulianne and Derek Hough. (credit:AP)
(14 of34)
Open Image ModalRyan and Mandi Gosling. (credit:Getty)
(15 of34)
Open Image ModalVanessa and Stella Hudgens. (credit:Getty)
(16 of34)
Open Image ModalZac Efron's little brother, Dylan. (credit:Pacific Coast News)
(17 of34)
Open Image ModalAdam and Michael Levine. (credit:Getty)
(18 of34)
Open Image ModalWhitney and Jade Port. (credit:Getty)
(19 of34)
Open Image ModalJames and Dave Franco. (credit:Getty)
(20 of34)
Open Image ModalBlake Lively's older brother, Eric. (credit:Getty)
(21 of34)
Open Image ModalPenelope Cruz's Sister, Monica. (credit:Getty)
(22 of34)
Open Image ModalScarlett Johansson and twin brother, Hunter. (credit:Getty)
(23 of34)
Open Image ModalElizabeth Olsen is the younger sister of Mary-Kate and Ashley Olsen. (credit:Getty)
(24 of34)
Open Image ModalBrad Pitt's older brother, Doug. (credit:Getty)
(25 of34)
Open Image ModalRobert Pattinson's older sisters, Lizzy and Victoria. (credit:Getty)
(26 of34)
Open Image ModalKate Hudson's older brother, Oliver. (credit:Getty)
(27 of34)
Open Image ModalJosh and Connor Hutcherson. (credit:Getty)
(28 of34)
Open Image ModalChord Overstreet's older brother, Nash. (credit:Getty)
(29 of34)
Open Image ModalDakota and Elle Fanning. (credit:Getty)
(30 of34)
Open Image ModalTaylor and Austin Swift. (credit:AP)
(31 of34)
Open Image ModalJake and Maggie Gyllenhaal. (credit:Getty Images)
(32 of34)
Open Image ModalMichelle Pfeiffer's younger sister, Dedee. (credit:Getty)
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Open Image ModalChris and Liam Hemsworth. (credit:AP)
(34 of34)
Open Image ModalBen and Casey Affleck. (credit:AP)