Diego Lopes has stunningly weighed in as a replacement fighter for Ilia Topuria vs Justin Gaethje.Topuria will defend his UFC lightweight title against Gaethje on the historic bill in front of the White House building this weekend.Topuria and Gaethje will headline the mammoth event, with millions of viewers expectedGettyThe once-in-a-lifetime event, that will mark US president Donald Trump’s birthday, has faced several logistical issues.One of the ways to ensure no late chaos takes place, is by ensuring the main event has a back-up fighter.Leading contender Arman Tsarukyan was originally the back-up fighter, waiting in the wings for a shot at the crown.But Tsarukyan hasn’t travelled to the US as he has his own wrestling outing, and is content in watching from home after placing a bet worth $1 million on Gaethje to win.Lopez weighs in to be Topuria vs Gaethje back-upIn some remarkable scenes from the morning weigh-ins, Brazilian star Lopez who is naturally a featherweight, stepped on to the scales.He was making the 145lbs limit for his own clash against Steve Garcia further down the card.But astonishingly after tipping the scales and making weight, the Brazilian took to the scales again just minutes later.Incredibly, after presumably rehydrating, he made weight at 154lbs, as if suitable for the 155lbs limit for a clash with Topuria or Gaethje.Lopes showed sensational professionalism in doing so, making him suitable for two specific fights.And as rumours gathered pace, that he would indeed be the stopgap in case of any disaster in the main event, the 31-year-old confirmed the news.Lopez has incredibly stepped on the scales twice, and is waiting in the wings if Topuria or Gaethje pull outGettyHe remarked: “People know how I am, they know I always like a challenge.“When we found out that Arman wasn’t coming anymore, we asked Hunter [Campbell, UFC CFO] ‘what can we do?’.“We said ‘we can offer to be the back-up if you like, we are here.’“Then he agreed and asked if I could weigh-in twice. I said yes and so we stepped on the scales twice.“I hydrated back up and did it, and now whatever happens we will be there.”It is preferable that the event can be saved with just one day out, to prevent any total disaster.UFC ScheduleFor all the upcoming fights and results this year, check out talkSPORT.com’s UFC schedule.But the likeliness of any late drama seems very low, given Topuria and Gaethje both made weight and looked fine on the scales.A disastrous late injury now has protection, but UFC kingpin White will hope his historic celebration goes on without any late mishap.