"Thank you for saying YES and making me the happiest man in the world," Tebow posted.
"You’re the love of my life, and I can’t wait to spend the rest of my life with you."
Demi-Leigh -- the 2017 Miss Universe winner -- also commented, saying, "Any dreams I’ve ever had, you’ve exceeded them all! I love you and I can’t wait to spend forever with you!"
Demi-Leigh is 23 years old. She's from South Africa. The two have been dating for a while and she recently went home to Florida with him to celebrate the holidays ... a big sign a ring was on the way.