Britain's Prince Philip, the husband of Queen Elizabeth II, has been hospitalized with a bladder infection, according to the Associated Press.
The prince, who turns 91 on Sunday, was taken to a London hospital on Monday as a precaution, the AP reports, and will remain under observation for a few days.
Philip will miss the Diamond Jubilee Concert scheduled for Monday night in front of Buckingham Palace, according to the AP. The concert features acts from the queen's 60-year-reign including Elton John, Paul McCartney, Cliff Richard, Stevie Wonder, Kylie Minogue and Will.i.am.
The AP also reported that the palace said Philip was "understandably, disappointed about missing this evening's Diamond Jubilee Concert."
He will also miss other jubilee events planned for Tuesday.
The queen will appear at the concert despite her husband's illness, a spokesman for the royal family told Agence France-Presse.
The prince, who underwent an emergency heart procedure in December, appeared in jovial form when he and the queen spent several hours Sunday in chilly conditions as they sailed down the Thames during a 1,000-boat pageant, AFP reported.
The prince married then-Princess Elizabeth in 1947. The AP reports he has cut back on official engagements in recent years but still maintains a busy schedule.