Mary Kate and Ashley Olsen

(credit: Stephen Lovekin/Getty Images)

Cynthia and Brittany Daniel

(credit: Stephen Shugerman/Getty Images)

Marissa and Giovani Ribisi

(credit: Charley Gallay/Getty Images)

Tamera and Tia Mowry

(credit: Frazer Harrison/Getty Images)

Angel (L) and Aaron Carter

(credit: Michael Buckner/Getty Images)

Cole and Dylan Sprouse

(credit:Gabriel Bouys/AFP/Getty Images)

Benji and Joel Madden

(credit: Brendon Thorne/Getty Images)

Jill and Jacqueline Hennessy

(credit: Joe Scarnici/Getty Images)

Jon and Daniel Heder

(credit: Vince Bucci/Getty Images)

Barbara and Jenna Bush

(credit: Andrew H. Walker/Getty Images)

Ann Landers and twin sister Pauline

(credit: AP)

Scarlett Johansson

Actress Scarlett Johansson has a twin brother named Hunter.(credit: Kevin Winter/Getty Images)

Linda Hamilton

Actress Linda Hamilton has an identical twin sister. Her sister Leslie played the part of 'T-1000 Sarah' In "Terminator 2." (credit: Marsaili McGrath/Getty Images)

Vin Diesel

Actor Vin Diesel has a fraternal twin brother named Paul Vincent. (credit: Joe Corrigan/Getty Images)

Keifer Sutherland

Actor Keifer Sutherland has a twin sister named Rachel. (credit: Frazer Harrison/Getty Images)

Joseph Fiennes

Actor Joseph Fiennes has a twin brother named Jacob. (credit: AFP/Getty Images)

Jeremy London

Actor Jeremy London has a twin brother named Jason. (credit: Dan Steinberg/AP)

Gisele Bundchen

Brazilian supermodel Gisele Bundchen presents an outfit by Colcci during the 2010-2011 Spring-Summer collection of the Sao Paulo Fashion Week, in Sao Paulo, Brazil, on June 13, 2010. AFP PHOTO/Mauricio LIMA (Photo credit should read MAURICIO LIMA/AFP/Getty Images)

Diedre Hall

Actress Diedre Hall has a twin sister named Andrea Hall-Gengler. (credit: Peter Kramer/Getty Images)

Alanis Morissette

Singer Alanis Morissette has a twin brother named Wade. (credit: Jason Merritt/Getty Images)

Ashton Kutcher

Actor Ashton Kutcher has a fraternal twin brother named Michael. (credit: Lisa Maree Williams/Getty Images)

Justin Timberlake

Justin Timberlake had a twin sister named Laura who died shortly after birth. (credit: Jason Merritt/Getty Images)

Elvis Presley

Rocker Elvis Presley had a twin brother, Jesse, who died at birth. (credit: AP)