Pour in a hot beverage of your choice and watch as your favourite BT21 characters appear from the black. When cold, this adorable BT21 Heat Changing Mug features the BT21 logo and the character VAN. However, once hot, the vibrant colours shine through and the rest of the cute gang appear on a bright blue background. This mug is a fantastic gift for BT21 fans, makes a great present at Christmas and birthdays, and is ideal for use at home or at work. BTS are one of the biggest boy bands in the world. The seven-member South Korean pop group formed in Seoul in 2013 and has since grown to global acclaim. The group have been known to put on fantastic live performances, and have staged several world tours. Their success led to the band making a $1m donation to Unicef and their growing popularity in the UK led to BTS appearing on the Graham Norton TV show. The boys at BTS partnered with popular Korean communication app Line, to create new Line 'characters' called BT21 that have taken the world by storm! These cute little characters originally appeared as emojis and electronic stickers, but later expanded to include fashion apparel, footwear, accessories, and other merchandise. This BT21 Heat Changing Mug is an officially licensed BT21 product.