Marc Spelmann is a magician who reached the semi-finals of Britain's Got Talent in Series 12. He received Ant & Dec's Golden Buzzer.

In his audition, Marc asked David to chose a colour of crayon, Alesha to choose a random animal from a pack of cards, Amanda to mix up a Rubik's cube randomly, and Simon to circle a word in a book, helped by the other Judges. He then revealed that, whilst revealing he knew each of the choices beforehand would be classed as 'magic', he discovered 'real magic' two years ago. He then played a video on the screen, explaining how his wife had been diagnosed with cancer, and that his daughter had to go through chemotherapy. He then revealed the correct answers to all four of the choices in the video, the word being said by his daughter two years ago. David, Alesha, Amanda, and Simon all gave him standing ovations. Moved by the performance, Ant & Dec pressed the Golden Buzzer for Marc, sending him straight to the Semi-final.

To begin his Semi-finals performance he read a quote that just so happened to be on a screen behind him and stated the words 'through times of challenge we often learn life's most valuable lessons'. He then went on to state how strong his wife Tessa was through her cancer, through her words he made the decision to appear on BGT. He showed the judges a piece he created two years ago, and gave Simon a gift of quote cards of quotes written by inspirational people, and asked him to pick one at random. He placed the card on Simons hand and asked him not to tell him what it said. He gave both Amanda and Alesha a book each of inspirational quotes, later gave David a copy of his own book Mr. Stink. David later had to insert a bookmark somewhere in the middle of his own book. Amanda then looked at the page in her book and kept it upright. David repeated what he did previously, yet this time with Alesha turning to the bookmarked page in her book and keeping it held upright. Simon then read the quote he had a second time. Both Amanda and Alesha had their books on the page of an author that they were familiar with. Simon then read out the final word of his quote which was 'heart'. He then told Simon he had to finish a piece of art, yet his daughter Isabella drew a picture for Simon which was kept in an envelope nearby him. Simon then opened the envelope and showed everyone what the picture showed as it was a drawing of a large red heart. Marc then completed his art as he played a VT of his wife and daughter. Alesha disclosed the author she was thinking of which was 'Ghandi'. Via the VT Marc asked Isabella to tell him who he'd been painting for the last two years, as she went on to reply 'Ghandi'. Amanda then visualised her person as Marc went on to mix up the pieces of his painting of Ghandi and create a new painting of John Lennon. Hidden in the image of Ghandi was also the image of John Lennon. He then went on to receive a standing ovation from the audience, and the judges. Amanda commented that the 'magic [was] extraordinary'. Simon added that 'magic [felt] too small for [Marc's performance].' David then went on to add that he believed that Marc made 'magic beautiful.' Alesha agreed with David feeling 'almost entranced' watching Marc's performance.

He reached the top three being beaten to winning the semi-final by Robert White, he then reached the judges' vote as he was sent home with two votes from David Walliams and Alesha Dixon, as the vote was later taken back to the public vote due to opposition Gruffydd Wyn receiving two votes from Simon Cowell and Amanda Holden. The public vote procceeded to send Marc home and Gruffydd through to the live final.