Steve Jobs sounds "healthy, energetic", according to Apple co-founder Steve Wozniak.

Speaking informally at the All Things D conference, Woz told the Wall Street Journal that the Apple CEO "'doesn't sound like he's sick', nor did he seem to be in a health crisis".

Steve Jobs has been on a leave of medical absence since January, because what was described as a "nutritional problem", later revealed to be "more complex" than was first thought.

He is due to return to Apple in June, although it was recently revealed that he won't be taking to the stage for the keynote speech at WWDC, the Apple event that kicks of on Monday 8 June.

Instead, the keynote will be delivered by a team of Apple executives, led by Philip Schiller, Apple's senior vice president of worldwide product marketing.