Former media baron Conrad Black returns to prison Tuesday to serve out the remainder of his sentence for fraud and obstruction of justice charges.

Black is scheduled to serve out an additional 13 months after Judge Amy St. Eve ruled earlier this summer his sentence was not complete.

Black, who has been free on bail since last summer, living in a five-star hotel in New York City, believes he will be released from prison in about eight months.

"I think that he's putting the bravest face on it that he possibly can," George Tombs, author of Robber Baron: Lord Black of Crossharbour, told CTV's Canada AM.

"To be going back to prison at the age of 67 for a 13-month stretch, especially in a federal penitentiary in the United States, is obviously very difficult."

The location where Black will be serving his sentence has not yet been released.

Lord Black of Crossharbour was convicted for obstruction of justice and three counts of fraud in a trial that ended in 2007. He was released last summer on US$2-million bail after a U.S. Supreme Court ruling on the "honest services" law used in his trial put his convictions into question.

However, St. Eve ruled in June that Black still has to serve 42 months less the 29 months he had already served, for a total of 13 months.

Black's wife Barbara Amiel, 70, who suffers from an autoimmune condition, collapsed in court when St. Eve handed down the decision.

Tombs said another stretch in prison will be difficult for the couple who will likely be permitted only one visit per week.

It isn't clear what will happen once Black's sentence is complete. He is no longer a Canadian citizen after former prime minister Jean Chretien enforced an archaic law that said no Canadian citizen could become a British lord, while also retaining their Canadian citizenship.

Black chose to give up his Canadian citizenship as a result of the high-profile battle. However, he told CTV's Chief Anchor and Senior News Editor Lisa LaFlamme in a recent exclusive sit-down television interview that he hopes to return to Canada once his sentence is complete.

Tombs said Black faces two years probation in the U.S. following hs release from jail. But since he isn't a citizen there either -- but rather is considered a non-resident alien scheduled for eventual deportation -- it isn't clear whether he'll be required to remain in the U.S. for his probation, or be allowed to serve it elsewhere.

"That's hard to take for someone who considered himself lifelong to be the greatest friend to the United States that there ever was, an expert on American politics, a friend of numerous presidents, secretaries of state et cetera," Tombs said.

Black still maintains his British citizenship and can return to the U.K. once his sentence is complete, if he chooses to do so.

At one time Black's media empire included the Chicago Sun-Times, The Daily Telegraph of London, the National Post and a handful of small papers across the U.S. and Canada.