Ninety-six-year-old Prince Philip missed a traditional Maundy church service that he was scheduled to attend Thursday with Queen Elizabeth II, raising concerns about his health.

The service is a traditional pre-Easter event held at St. George’s Chapel at Windsor Castle.

The prince’s last-minute decision to skip the service was related to some “trouble with his hip,” a source told People magazine.

The prince previously missed son Prince Andrew’s March 22 appointment as colonel of the Granadier Guards, the magazine reported.

He announced in May 2017 that he planned to step away from many traditional royal duties beginning last fall.

Prince Philip and Queen Elizabeth have been married since 1947. Elizabeth became queen in 1952, following the death of her father, King George VI.