The King of Spain has arrived at a Madrid hospital where he is to undergo surgery for a herniated disc in his lower spine.
It will be Juan Carlos' fourth operation in 12 months, and the 12th time he has undergone surgery during his lifetime.
The 75-year-old monarch lowered his passenger-side car window and said, "Here I am again," to journalists and television cameras gathered outside La Merced clinic on Sunday.
The operation will be led by neurosurgeon Manuel de la Torre, a palace statement said.
The head of state had hip surgery last November and has suffered several other health issues in the past two years, including knee surgery and the removal of a benign lung tumor.