Thomas says he wants to show how people with HIV are misrepresented as “walking around with walking sticks who are close to dying”.
He has also spoken about “shame” and “fear” of keeping his condition secret.
The ex-British and Irish Lion is due to talk about his diagnosis in a BBC Wales documentary on Wednesday.
In it, he says at his lowest point in 2018 he felt like dying.
Thomas said revealing that he is living with HIV was similar to coming out as gay in 2009 because of “the fear, the hiding, the secrecy, the not knowing how people are going to react”.
“But I think when it was all about my sexuality it just seemed like there was more empathy and more understanding because you had more knowledge, because you could turn on the telly and you could see that there was LGBT representation on most platforms.”
Thomas plans to take part in an Ironman challenge on Sunday, which has involved him learning to swim, were to Thomas a way of demonstrating his physical and mental strength.