At least two chihuahuas were used in the adverts. The original dog cast for the lead role was named Dinky, but was replaced at the last minute by director Kinka Usher with Gidget, who was originally cast as the chihuahua's girlfriend. Another chihuahua called Taco was a stand-in for Gidget.
A book about Gidget's life titled A Famous Dog's Life: The Story of Gidget, America's Most Beloved Chihuahua was published by Sue Chipperton and Rennie Dyball on May 3, 2011.
Gidget was born on February 7, 1994 in Los Angeles, California. She was adopted by Karen McElhatton and trained by Sue Chipperton. In September 1997, she starred in her first Taco Bell advert, which involves a male chihuahua (portrayed by Gidget) noticing a female chihuahua waiting for him and he falls in love. He runs over to her to greet her, only to run past her (which embarrasses and disappoints her), instead running over to a man eating a taco. He gets his attention by staring at him and saying "Yo quiero Taco Bell!". In response, the man stares blankly at Gidget, shocked that he spoke to him.
In 2000, Gidget's Taco Bell ad campaign was cancelled after complaints that the adverts were racist, made fun of Mexican people and full of Hispanic culture stereotypes. This led to rumours the advers were cancelled because she had died (which wouldn't happen for another nine years). She then pursued other acting work, reassuming her role as the Taco Bell Chihuahua in a 2002 advert for GEICO (alongside the GEICO Gecko mascot) and as Bruiser's mother in Legally Blonde 2: Red, White & Blonde the following year.
After her retirement, Gidget would often go on hikes and beach visits with her trainer, Sue Chipperton. She aged gracefully and liked to sleep in the sunlight. Karen McElhatton also said, "She was like a little old lady. She'd kind of gotten smaller."
On July 21, 2009, Gidget had to be put down after suffering a massive stroke at the age of 15 in Chippeton's home. She was cremated and her ashes were retained by Chipperton. This was just a day after Carlos Alazraqui's 47th birthday and he also mourned Gidget's death. In a statement, Taco Bell Corp. said that Gidget would be missed by many fans and said, "Our deepest sympathies go out to her owners and fans."