Well, it might not be new System of A Down, but frontman Serj Tankian lended his vocals to the song O.R.K.'s 'Black Blooms' which appears on O.R.K.'s new album, Ramagehead, out Feb. 22nd.
O.R.K. is Lorenzo Esposito Fornasari a.k.a Lef (lead vocals), King Crimson's Pat Mastelotto (drums), Porcupine Tree's Colin Edwin (bass), Marta Sui Tubi's Carmelo Pipitone (guitar).