A statement on his website says that the operation at St. George's Hospital in south London to remove the tumor lasted five hours and was a "complete success."
According to the BBC, the growth, a pituitary adenoma, was removed through Watson's nose. Bill Holland, managing director of Watson's record label, Universal Classics and Jazz, told the BBC, "They had to be very careful the way they did it, because of his vocal cords, we had to ensure that there'd be no damage."
Recording for Love Affair has been put on hold; the release date, which was scheduled for November, has been moved to early 2007. Russell is expected to be fully recovered in time for an upcoming UK tour in November and December.
Watson initially continued to record in the studio last week after being examined in the US, even though he was reportedly in severe pain.
The English tenor, 39, used to be a factory worker before he became a singer. He has sold more than 4 million albums worldwide.