How is DevOps related to Agile?

Agile has been around for quite a while. And several offspring came out of it, such as Extreme Programming, Scrum, Lean Software Development and others.

Isn't DevOps just another offspring of Agile? Is there any substantial difference between DevOps and Agile?

Answer

I rephrased the question, but it is different enough to have its own question - http://devops.stackexchange.com/questions/333/does-my-organization-need-to-be-agile-before-adopting-devops