Former President George HW Bush was hospitalized after Super Bowl coin toss

The hospitalization was not previously disclosed.

His staff did not announce that hospitalization until today, without clarifying why Bush, 92, needed medical attention.

More recently, his staff announced that he was hospitalized last Friday "for observation due to a persistent cough that prevented him from getting proper rest. It was subsequently determined he had a mild case of pneumonia, which was treated and has been resolved."

He tweeted a picture of himself at the hospital Thursday joined by his son former President George W. Bush.

Bush spokesman Jim McGrath today said doctors expect to keep the former president in the hospital through the weekend to "ensure a fully clean bill of health."

ABC News' Gina Sunseri contributed to this article.