Speaking on The Jonathan Ross Show, the Olympic diving hero says that "it really was love at first sight, I'd never felt like anything like it before."
He goes on to explain how he met his boyfriend, who is rumoured to be American screenwriter, Dustin Lance Black: "We were at a party and I hadn't even spoken to him all night. I didn't know what to do or if he was gay at first."
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But Tom took the first step: "I typed 'call me' in his notes with a smiley face on this phone and the next day he texted. He makes me feel safe and happy, right now I couldn't be happier."
The 19-year-old opened up on the ITV show – to be aired on Saturday 7 December – around the same time that he filmed a five-and-a-half-minute video which he circulated on Twitter with the caption: "Got something I need to say...not been an easy decision to make, hope you can support me!"
Speaking out for the first time in public since, he said, "I'd never felt the feeling of love, it happened so quickly, I was completely overwhelmed by it to the point I can't get him out of my head all the time.
"I've never had it before where I love someone and they love me just as much."
He also credits his new-found love with keeping him swimming after the London 2012 Olympics.
"He saved me from not wanting to dive anymore," Tom says. "After the Olympics I was down in the dumps, as it’s such a hard way to get back into everything, but he gave me the extra motivation and made me work harder and that is exactly what I need."