Kristina and Karissa Shannon

In 2008, the Shannons moved into the Playboy Mansion as two of Hugh Hefner's three new girlfriends; because of their relationship with Hefner, the Shannons began appearing on the E! network reality television series The Girls Next Door. Despite their "girlfriend" status, Karissa said the relationship she and Kristina shared with Hefner was more for fun and the opportunity to be on the show, rather than romance. The first episode they appeared in attracted 2.4 million viewers, making it the most-watched season premiere in the show's history;^[1] five weeks after the premiere, viewership had dropped to 919,000.^[2]

The Shannons appeared as Miss July and Miss August 2009 in the combined "summer issue" of Playboy magazine; the double issue was necessitated by financial problems at the publisher.^[3] Unlike previous centerfold twins, they managed to earn two consecutive months as Playmates, but shared a single centerfold.^[4] By January 2010, the Shannon twins moved out of the mansion, though they continued to appear in The Girls Next Door.

The twins had small roles in Somewhere, a film directed by Sofia Coppola which won top honors at the 67th Venice International Film Festival in 2010.^[5]

On January 5, 2012, the twins participated in the ninth series of the UK reality show, Celebrity Big Brother in which they came fifth. They also appeared on the companion series to the show, Big Brother's Bit on the Side.^[6][7]

The twins were raised in Clearwater Beach, Florida and attended Largo High School for a time.