In 2021 Darrel performed as guest musician for Gary Hughes’ new solo album Waterside in which he played keyboards and acoustic drums. He also created and produced the sleeve/booklet art for both Waterside and the double-album best of compilation titled "Decades" also by Gary Hughes and released by Frontiers Records. In October 2021, Treece-Birch performed on the debut studio album entitled Prophecy by the British melodic Hard Rock band TAO.
