After thousands applied and hundreds auditioned, the search reaches the live semi-finals. The final 40 acts now perform live in the hope of impressing the judges, as well as winning the all-important public vote. Across the week our Kings and Queens of entertainment, Simon Cowell, Amanda Holden, Alesha Dixon and David Walliams will welcome eight acts to the stage to perform for a chance of winning a life-changing 250,000 pounds and a spot at this year's Royal Variety Performance. Each night two acts will go through to the live Grand Final. As well as performances from this year's acts, a host of guest performers will take to the stage during the results shows as the semi-finalists wait to find out if they are one step closer to being crowned winner of Britain's Got Talent 2018.