Former Illinois Gov. James R. Thompson is recovering after undergoing emergency surgery to remove a blood clot from his brain.

Thompson, 68, complained of a severe headache Friday night and was advised by his doctor to go to the emergency room, where doctors diagnosed the blood clot, said Chris Robling, who was acting as a family spokesman.

Doctors at Northwestern Memorial Hospital on Saturday morning performed the surgery, called a craniotomy, to remove the clot, Robling said.

By Sunday afternoon, Thompson the state’s longest-serving governor was calling friends and family and doing telephone interviews from his hospital bed in the intensive care unit.

“I’m feeling pretty good for having 3-hour surgery yesterday,’’ Thompson told WBBM-AM. ” ... I’m going to watch the Super Bowl tonight. Not exactly where I thought I’d be watching the Super Bowl tonight, but I’m glad I’m watching it.’‘

Thompson slipped and fell on ice near his Chicago home in early January, hitting his head and blackening his eye. Doctors believe the fall caused cranial bleeding that resulted in the blood clot, his wife, Jayne Thompson, said Sunday afternoon.

Two weeks ago Thompson began experiencing headaches that got progressively worse, culminating in Friday’s visit to the emergency room, she said.

“He described it as ‘the worst headache I’ve ever had,’‘’ Jayne Thompson said.

Doctors expected Thompson to be out of intensive care in the next one to two days and home by the end of the week, his wife said. He will also recuperate for some time at home.

A former U.S. attorney in Chicago, the Republican Thompson served as governor from 1977 to 1991, when he chose not to seek re-election.

Thompson, who is the chairman of the high-powered law firm Winston & Strawn, served on the federal commission that investigated the Sept. 11 terrorist attacks.

Jayne Thompson said it has been a stressful week for the family. Agnes Josephine Thompson, James Thompson’s mother, died Jan. 28 of natural causes at the Lutheran Home in the Chicago suburb of Arlington Heights. She was 96.