Steve Jobs reportedly returned to work Monday after the liver transplant that the Apple co-founder and chief executive is said to have undergone two months ago.

Jobs has been on medical leave since January. Apple had said that he was due to return, initially on a part-time basis, at the end of this month.

However, Jobs was seen by several people at the Apple headquarters in Cupertino, Calif. Monday, fuelling speculation that he had returned to the helm earlier than expected.

• Click here for more photos.

• Click here for FOXNews.com's Personal Technology Center.

• Got tech questions? Ask our experts at FoxNews.com's Tech Q&A.

In early January Jobs said that he was suffering from “a hormone imbalance." Less than a week later, he said that his health issues were “more complex than I originally thought” and that he was taking medical leave for six months, putting Tim Cook, the chief operating officer, in charge of day-to-day operations.

The Wall Street Journal reported last weekend that Mr Jobs had undergone a liver transplant recently. Yesterday, Apple shares fell more than 2 per cent at one point as markets reacted to the news. Investors worried about the chief’s long-term health sent Apple shares down to $136.50 before closing at $137.37, down 1.5 per cent.

Click here ro read more on this story from the Times of London.