The Daily Express is reporting that a BBC mole has told them that Tom Baker will be returning to the series after over twenty-eight years to appear alongside the 11th Doctor Matt Smith.
Tom Baker played the fourth Doctor, from 1974-1981, and is widely considered to be the most popular and iconic of the classic series Doctors, only surpassed in worldwide popularity by David Tennant in recent years.
The BBC has not officially announced this, and even if it’s true are not likely to announce it anytime soon since Smith won’t be taking over the role until 2010.