Calum and his sister Jade auditioned separately one before the other. Jade went on first but her performance was said to be off-key and was sent off. A nervous Calum then stepped onstage. He sang Robyn's "Dancing On My Own". Following a standing ovation, Simon pressed the Golden Buzzer giving Calum an automatic place in the live shows.
In the semi-finals, Calum performed 'We Don't Have to Take Our Clothes off' by Jermaine Stewart. A close-up of his face was being projected on the screen behind. Simon Cowell commented 'You really sound like a recording artist', whilst David Walliams suggested that he could have 'success around the world'.
In the final, Calum performed 'Diamonds' by Rihanna. He stumbled over his words in the first verse, however he continued to finish the song. He finished 6th out of 12 contestants.
After BGT Edit
In 2016, he released a cover of Robyn's 'Dancing on My Own' which peaked at #2 and spent over 30 weeks in the Top 40.