Tom Daley hid an engagement ring in his underwear when he proposed to Dustin Lance Black.

Tom Daley and Dustin Lance Black

Tom Daley and Dustin Lance Black

The 21-year-old Olympic diver popped the question to the American screenwriter in September after three years of dating, but admitted his lover's subsequent proposal to him was much more extravagant.

Speaking to Out magazine's Love issue, he said: "I had the ring box in my underwear, and when he came out of the bathroom, I just went down on my knee and proposed.

"Then he ran off to the bathroom to get his rings, and he had this whole speech prepared, but he's a writer so his was quite extravagant."

Though they had been together for three years before getting engaged, the couple knew within just weeks of dating that they wanted to tie the knot.

Tom said: "Quite honestly, we talked about marriage within the first two weeks after seeing each other the first time in LA.

"That was the weird thing: that it came up in conversation so many times. I always knew it was going to happen at some point."

Dustin, 41, added: " We were so busy making all these plans -- we both wanted to have children; we both wanted to build a home of our own someday.

"I draw, so I was sketching little plans for houses on cliffs overlooking oceans, while Tom watched over my shoulder -- it was a very grown-up version of playing house.

"Marriage is the foundation to all of these other big plans we have. So we knew we were going to get engaged -- it was just a matter of when, and who does it."