The 45-year-old TV writer and producer was found dead in a motel room in Miami on Tuesday.
According to Variety Horta died from an apparently self-inflicted gunshot wound and his death is being treated as a suicide.
But while a representative for the award-winning Miami-born writer confirmed his death they declined to comment on the circumstances.
Ugly Betty star America Ferrera is among those to lead tributes to Horta.
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She wrote on Instagram: “I’m stunned and heartbroken to hear the devastating news of Ugly Betty creator, Silvio Horta’s death. His talent and creativity brought me and so many others such joy & light. I’m thinking of his family and loved ones who must be in so much pain right now- and of the whole Ugly Betty family who feel this loss so deeply.”
Vanessa Williams, who played the villainous Wilhelmina Slater in the hit show, wrote: “Still in shock after hearing the tragic news of our #uglybetty creator #silviohorta 💔 His creativity and passion will be missed by so many of us that worked with him. May he Rest In Peace.”
Ugly Betty - about a young geeky girl who lands a job at a top fashion magazine - ran for four seasons from 2006 to 2010.
It garnered multiple award nominations winning Golden Globes, Emmys and a Writers Guild award for best new series in 2007.
Scottish actress Ashley Jensen had her Hollywood breakthrough in the show as Betty’s friend Christina McKinney. Due to the show’s success in the UK it was nominated for an NTA in 2008.
Salma Hayek was an executive producer on the show.