In an interview with Fenuxe, Thompson -- who is called "Uncle Poodle" on the show -- says that he was diagnosed in May.
"I knew it had been my boyfriend who infected me," Thompson told the site. "I later learned he had been HIV positive and was not taking medication and had not bothered to tell me about it. I was advised that I should press charges and, hesitantly, I did. It was the right thing to do."
Thompson's ex is currently serving a five-year sentence because of the deception, Thompson told the site.
"I would have been cool with his HIV status if he had been honest," Thompson said. "I don't have an issue with the disease. I would have known how to protect myself."
A spokesman for TLC had no comment for TheWrap on Thompson's revelation.
"Boo Boo," the hit "Toddlers & Tiaras" offshoot, follows child beauty-pageant participant Alana "Honey Boo Boo" Thompson and her family in rural Georgia. Thompson is a recurring cast member.
Thompson offered a blunt assessment of those who have unsafe sex.
"They are damn fools!" Thompson said. "They are playing Russian roulette; they are playing with their lives and that of their sexual partners."
Thompson told the site that he wants to use his celebrity status to combat bullying and promote safe sex -- and perhaps parlay his experience into a future TV gig.
"I want to have my own television show and highlight what it is like being gay in the south," Thompson said. "I think I have a good story to tell."