no TopFlix. UFC on Fox 25: Weidman vs Gastelum was a mixed martial arts event produced by the Ultimate Fighting Championship held on July 22, 2017 at the Nassau Veterans Memorial Coliseum in Uniondale, New York. The event was headlined by a middleweight bout between former UFC Middleweight Champion Chris Weidman and The Ultimate Fighter: Team Jones vs. Team Sonnen middleweight winner Kelvin Gastelum.[