In early July, Jaguar will lift the covers off its Mercedes-Benz S-Class rivaling, 2010 XJ luxury sedan, ahead of the car’s market debut at the end of the year. Following the release of a set of teaser photos at the Shanghai Auto Show in April, Jaguar has now published a short video interview with the British firm’s design chief, Ian Callum who talks about the design philosophy behind the new XJ. Among other things, Callum claims that with the new XJ sedan, Jag’s design team “took 30 years of learning and put it into something that is very complete.” Hit the jump to watch the video but don’t get too excited…