EXCLUSIVE: 'Big Brother' 19 Winner Josh Martinez Says He's 'Completely Shocked' By His Victory: 'It's Crazy!'

After one of the most contentious seasons in Big Brother history, houseguest Josh Martinez walked away victorious on Wednesday, and the 23-year-old Miami native said the outcome came as a total surprise.

ET's Brice Sander caught up with the season 19 champ after his big win, where Martinez admitted he never thought he had a chance after getting into the final three against odds-on frontrunner Paul Abrahamian and Christmas Abbot.

"No shot, not at all. I don't even know what's going on," he exclaimed. "I don't even think I won. It's crazy… I'm completely shocked."

After a bitter and aggressive jury segment, Big Brother 19's finale came down to the vote of Cody Nickson, who had been a rival of both Martinez and Abrahamian throughout the season. 

After deliberation, Nickson ended up casting the winning vote in Martinez's favor, and it was that vote that surprised the champ the most.

Nickson -- who walked away with $25,000 after winning the title of "America's Favorite Houseguest" -- explained that he voted for Martinez because he was upfront about their rivalry while Abrahamian was duplicitous.

Whether Martinez believes it or not, he's now looking at a $500,000 grand prize -- and the reality star says he really doesn't know what he's going to do with it, but he's pretty sure he wants to hire an accountant. Then, after a promised "world tour" with a few of his fellow houseguests, he wants to treat his mom and dad to something special.

"[I'm gonna] give back to my parents," he said. "They don't want anything, they're like, 'Go start your life,' but I wanna give back to them."

As for whether or not he'd ever have an interest in being a houseguest again, Martinez said there's no question about it -- after he's had a little break, of course.

"Give me six months and I'll jump right back in, pots and pans and all," he declared.

For more on this dramatic season of Big Brother, check out the video below.