Spain's King Juan Carlos presided over a military parade wearing crutches on Monday, his first appearance in public outside his home since undergoing hip replacement surgery in November.
Wearing a brown military uniform, the king, who turned 76 on Sunday, thanked Spain's armed forces for their "commitment and hard work" in a speech at the Royal Palace following the parade.
The ceremony was shortened for the second straight year because of the king's difficulty in walking following several hip operations.
During his most recent procedure in November, surgeons replaced his left hip, his ninth operation since May 2010.
Juan Carlos is widely respected for his role in Spain's transition to democracy after the death of dictator General Francisco Franco in 1975.
But his popularity has plunged over the past three years, largely due to a corruption scandal centred on his son-in-law and a luxury elephant-hunting trip the king made to Africa in 2012.
His health problems together with the scandals have raised speculation about the future of his reign.
Sixty-two percent of Spaniards want Juan Carlos to abdicate and fewer than half support the monarchy in general, according to a poll published on Sunday in El Mundo.
The royal palace and the king firmly denied any thoughts of an abdication.
"I want to express to you, as King of Spain, my determination to continue the faithful fulfilment of the mandate and the powers attributed to me that the constitutional order," the king said in his annual televised Christmas address last month.
A judge since 2011 has been investigating alleged embezzlement by the husband of his youngest daughter Cristina, former Olympic handball player Inaki Urdangarin.
The judge in that case is also due to rule on whether to summon Cristina herself as a formal suspect for alleged tax evasion and money laundering.
The king also lost sympathy last year for going on an expensive elephant-hunting trip in Botswana while Spaniards struggled through a recession.