Boxing legend Ali in hospital

According to spokesman Bob Gunnell, the 72-year-old is expected to recover due to the illness being caught early.

Ali is being treated by a team of doctors and remains in a stable condition. 

"Because the pneumonia was caught early, his prognosis is good with a short hospital stay expected," Gunnell said in a statement.

The former heavyweight champion, who suffers from Parkinson's disease, was seen in September to attend a ceremony in Louisville, Kentucky, for the Muhammad Ali Humanitarian Awards.