Big Vinny (who's not so big anymore) is getting married!

The Trailer Choir singer and current contestant on NBC's hit show, 'The Biggest Loser,' proposed to his longtime girlfriend, Lori Diaz, at the Grand Ole Opry for a date that was filmed as part of the reality TV show.

"I wanted to take her there because it's a place where so many dreams have come true, right there on that stage," Big Vinny (whose real name is Vincent Hickerson) tells People. "My biggest dream is to be a great husband and a great father, and fall in love."

"There was no one there but us and a camera crew," Lori adds. "We sat down in the front row and he [gave] me a spiel about how he loves me more than anything."

Their evening was capped off with a private performance by duo Thompson Square. "I couldn't believe they were there just for us, in this huge, amazing place," the bride-to-be gushes.

Vinny sealed the deal with a ring from a local Nashville jeweler. "I thought it looked like the Eiffel Tower, which makes people think of beauty and romance," notes the tunesmith. "Just like the first time I saw Lori, out dancing in a zebra dress, I had that same feeling like, 'Oh my gosh, this is the one.'"

Their upcoming nuptials will make Big Vinny a step-dad to Lori's 9-year-old son, Brennon, who was a big part of his weight loss inspiration. "I wasn't out playing ball with Brennon and even watching him skateboard. I'd just sit in the car and watch," says the newly svelte singer, who is currently down to 314 lbs, after beginning his weight loss journey at 426 lbs. "Now, there isn't anything I can't do!"

Watch 'The Biggest Loser' tonight (Dec. 6) at 9:00 PM ET. We'll find out if Big Vinny wins the show on the Dec. 13 finale.

Watch Bob Harper on 'The Biggest Loser'