Here are the performers and contestants who will be giving it their all once more in this season's semifinals.
The 'Saturday Night Live' star sat in for the longtime judge on Tuesday.
Kelly Clarkson previously stepped in after Cowell injured his back earlier this month.
The 'AGT' judge broke his back in an electric bike accident earlier this month.
ET has learned that the 60-year-old 'America's Got Talent' judge is walking again as part of his recuperation.
Kelly Clarkson filled in for Cowell as he recuperates from back surgery.
The 'America's Got Talent' judge is continuing to recover in the hospital.
ET has learned that Simon Cowell underwent six hours of overnight surgery on Saturday, after breaking his back in a number of places.
ET exclusively spoke with Simon Cowell and Sofia Vergara ahead of the show's return to NBC on Tuesday.
Kelly Clarkson is stepping in for Simon Cowell on Tuesday and Wednesday's live shows for 'America's Got Talent.'
Simon Cowell was excited about a big return to filming live telecasts of 'AGT' just one day before breaking his back.
The "America’s Got Talent" judge is sharing some advice with fans after breaking his back in a biking accident.
Cowell went through six hours of surgery after breaking his back on Saturday.
The 'America's Got Talent' judge has undergone surgery.
