Ed Sheeran, Anne-Marie and KSI also set to perform.A statement on the official Capital FM Instagram page read: ‘We’re so sorry to say Mabel is no longer able to perform at tonight’s Jingle Bell Ball with Barclaycard.‘Some members of her team have tested positive for Covid-19, so she has to stay at home until she gets the all clear.‘Mabel’s asked us to say how sorry she is that she can’t join us tonight, she was so looking forward to perform with everybody and she hopes to see everyone again soon.‘We’re delighted to confirm after his sensational performance last night, Tom Grennan is stepping back up to the plate tonight.‘Tom joined a HUGE show with Ed Sheeran, Anne- Marie, KSI, and loads more all set to take to the Jingle Bell Ball.