O.J. and Kato Dined at the Santa Monica McDonalds

According to the prosecution, Simpson was last seen in public at 9:36 p.m. that evening when he returned to the front gate of his house with Brian 'Kato' Kaelin, a bit-part actor and family friend who lived on the property of Simpson's estate, after the pair ate at a nearby McDonald's.

Brian Gerard "Kato" Kaelin (born March 9, 1959) is the one-time house guest of O.J. Simpson who became peripherally involved in the 1994–95 O.J. Simpson murder case and subsequent trial. At the time of the trial, he was an aspiring actor.

Kaelin was nicknamed "Kato" as a child after the character played by Bruce Lee in the television series, The Green Hornet. He graduated from Nicolet High School in Glendale, Milwaukee County, Wisconsin in 1977. He attended the University of Wisconsin–Eau Claire, where he was the game show host at the student-run, campus TV station, TV-10. He subsequently moved to Los Angeles, California, to pursue a career in baseball.

He was married to Cynthia Coulter from 1983 to 1989; they have one child. He has also dated Elizabeth Daily.Kaelin was "best friends" with actor/comedian Norm Macdonald from mid 2000 to mid 2001 according to Macdonald's The Norm Show co-star Artie Lange. Kaelin was even given a guest role on said show. The two had a "falling out," ending their friendship.

Kaelin came to notice for his role as a minor witness in the trial of O.J. Simpson for the murders of Simpson's ex-wife Nicole Brown Simpson and her friend Ronald Goldman. In 1994, Kaelin was staying in a guest house on the Simpson property, and was present at the compound on the night of June 12, witnessing some of Simpson's movements before and after the time of the murders. Kaelin's story seemed to contradict Simpson's version of the events on some key points. However, his rambling and inconsistent testimony over four days of the 1995 criminal trial made him a less-than-ideal witness for the prosecution. Prosecutor Marcia Clark had him declared a hostile witness. Kaelin also testified at the 1996 civil trial against Simpson.As one of the more colorful figures in the Simpson case cast of characters, Kaelin received considerable media attention. He was the subject of jokes by TV comedians, who made fun of his spaced-out surf bum persona, lack of employment, and parasitic habits. One popular joke held that he was proof that Gilligan and Ginger Grant of Gilligan's Island had actually had children.

Prior to his involvement in the OJ Simpson trial, he was in an early 1990s movie called Beach Fever, in which he created a love potion with his friend and hit on girls at the beach, and starred in a low budget crime movie Night Shadow in 1989. He also had a minor role in National Lampoon's Dorm Daze 2.In 1998, Kaelin went on a speaking tour billed as the The Sixteenth Minute, talking about life after his fifteen minutes of fame.Kaelin appeared on the first episode of the Fox sketch comedy MADtv (Oct. 1995) and also made a cameo appearance on the HBO sketch comedy, Mr. Show, during the show's first season (Nov. 1995) - in the episode entitled "We Regret to Inform You", he shows up at lobotomized actor Borden Grote's party.He has made numerous forays into reality television. In 2004, participated in the development of a 2004 reality show called House Guest where he would live in the homes of other (minor) celebrities. The show never aired. He was seen on an episode of the E! reality series Sunset Tan, asking specifically for a "farmer's tan". He was also a guest player on the 6th episode of the Comedy Central series Reality Bites Back. As of 2008, he is a contestant in the Fox Reality reality show Gimme My Reality Show, in which D-list celebrities compete to receive their own reality show.He has also participated in game shows. He was a contestant on the hit game show Russian Roulette. In 2005, Kaelin appeared in the first three National Lampoon's Strip Poker pay-per-view programs (Kaelin is an avid poker player). The titles were filmed at the notorious Hedonism II, a naturist resort in Negril, Jamaica, which led Kaelin to quip, "The first few days there were the hardest!" The Playboy bunnies, WWE Divas, and pin-up models competing in the no limit Texas hold 'em games, upon losing all their chips and clothes, had to dive into the "Pool of Shame" and visit "Kato's Guesthouse," where Kaelin would interview the nude defeated players. Kato also appeared in numerous comedic skits.He also has worked as a host on television and radio. For a short time in 1995 he worked as a radio talk host on KLSX in Los Angeles, and also provided online content for National Lampoon. In June 2005, Kato Kaelin began to host Eye for an Eye, a daytime TV court show that is in syndication in 34 countries. Kaelin is a recurring guest on the video game review show X-Play. He has also appeared periodically as a guest co-host for Confessions Live, a syndicated call-in talk show that was produced in Arkansas.In February 2009, Kaelin guest-starred in the web series Star-ving and the movie Whacked.He also appeared as a "not famous celebrity" on the TV show Reality Bites Back.