Travis Barker has joined Machine Gun Kelly onstage for his first performance since being hospitalised with pancreatitis last month.The Blink-182 drummer made a surprise guest appearance at Kelly’s show in Los Angeles on Wednesday night (July 13), as part of the latter’s ‘Mainstream Sellout’ tour.As per Page Six, Kelly introduced Barker by saying: “There’s a person I grew up idolising that I became friends with and he believed in me. And never more have I wanted to jam to a song that he and I created.”“You know a fun fact is that Travis is not supposed to be playing drums right now but guess what he’s doing here? Playing drums right now!” he added.