The valuable cello was apparently damaged while being handled by experts during a photo shoot at the Royal Palace in Madrid.
The cello is part of a quartet of valuable instruments kept at the Royal Palace in Madrid, which includes two Stradivarius violins and a viola.
El Mundo newspaper (Spanish language) reported that the cello fell from a table during a photo shoot.
A National Heritage official has declined to say exactly what happened but did confirm that it occurred around three weeks ago. She spoke on condition of anonymity, in line with department policy.
Apparently a piece that joins the neck of the 17th-century cello to its body was broken. This piece was not original but was a replacement installed in the 19th century and the Palace states that this can be repaired. A photo of the damaged cello can be viewed here.
The Stradivarius cello was acquired as part of a set by King Felipe V of Spain in the 18th century.
Musical instruments by Stradivarius are well-known worldwide as being the greatest ever shaped by the hand of man. Antonio Stradivari created around 1,000 violins, cellos and guitars in the late 17th and early 18th centuries. However, today only around 650 exist and these instruments are only played by world-class musicians.