Placido Domingo is in hospital in Spain after suffering a blockage in an artery of the lungs.
The opera singer's publicist says the 72-year-old is expected to make a full recovery but will have to miss at least two performances that were scheduled for later this month.
He was admitted to the hospital in Madrid on Monday (July 8).
Doctors say the pulmonary embolism was caused by a blood clot.
Publicist Nancy Seltzer said doctors have asked the Spanish tenor and conductor to rest for three to four weeks, but that healing time varies. His return to the stage will depend on how quickly he regains his strength.
Domingo has cancelled his performances in Daniel Catan's Il Postino, which were to begin on July 17 at the Teatro Real in Madrid, as well as an appearance on July 21 at Plaza Mayor.