Travis Barker was 'hands on' with Kourtney Kardashian's engagement ring

Schwartz told People magazine the rocker was actively involved in the design of the huge oval shaped diamond which she said is "a flawless, beautifully cut diamond stone."

"I worked on it with Travis and he was a really big part of it," Schwartz told the publication. "He was really hands-on in the whole making of it. It's gorgeous and they're happy."

In the September issue of Nylon magazine, Barker talked about how his love for Kardashian helped him overcome his fear of flying following a 2008 plane crash which killed two of the pilots and two of his friends and left Barker severely injured.

Their relationship, he said, gave him "the strength and hope to be able to overcome things that were so traumatic in my life."