Jonathan Jacob Walker (born September 17, 1985) is an American musician, singer, songwriter, and record producer. Formerly the bassist of Panic! at the Disco, Walker was also the guitarist and co-vocalist of The Young Veins (which he founded with former Panic! at the Disco guitarist and songwriter Ryan Ross), which is now on indefinite hiatus. Having gone on to release several solo recordings, he is now mostly songwriting and producing.