MTV has lost the executive most instrumental to the development of its new Urge digital music service.

Jason Hirschhorn, global digital officer of MTV Network, has chosen to leave the company to pursue new start-up opportunities, reports claim. Nick Lehman, executive vice president of digital media, will take over while a replacement is found.

Hirschhorn launched Mischief New Media six years ago, which was later acquired by MTV.

Judy McGrath, chairman CEO of MTV said: "Jason is a visionary who has been a driving force during the transformation of MTV Networks from a linear cable programming company to a digital, multiplatform powerhouse."