DJ HEARTSTRING is a Berlin-based German DJ and production duo made up of Jonas Hellberg and Leonard "Leo" Hans Victor Brede. The project formed in 2021 and is associated with a trance-leaning electronic style that blends Eurodance, techno, and pop elements. The duo first gained attention with releases such as their early EPs and later remixes for artists including Charli xcx, Romy, and Ciara. Their output is centered on club-oriented tracks and DJ sets, and they have performed at festivals and clubs across Europe and beyond. Their live format is primarily as a DJ act, presenting high-energy electronic sets rather than a conventional band performance.