Sam Hollander is an American songwriter. He has collaborated with Panic! at the Disco, One Direction, Fitz and the Tantrums, Def Leppard, Weezer, blink-182, Train, Billy Idol, Carole King, Katy Perry, Boys Like Girls, Metro Station, Daughtry, Gym Class Heroes, Tom Morello, among others.

Source: Wikipedia (https://en.wikipedia.org/wiki/Sam_Hollander)