The 24-year-old model is completely smitten with the professional baseball player and can't wait to spend the rest of her life with him, reported Feamle First.
"I'm marrying my best friend. He's smart, funny, honest, optimistic, thoughtful, kind - just the best," Upton said.
The couple announced their engagement in May when Upton showed up to the Met Gala with a beautiful piece of bling on her finger but the couple had been keeping the news "on the down low" for some time.