The invention is related to an adjustable spacer (1) for adjusting a spacing between a first component and a second component to a predefined distance, comprising: a support component (2) configured to be rigidly mounted to the first component; a spacing component (3) movably mounted to the support component (2) for adjusting positioning of the support component (2) relative to the second component; and a fixing component (4) configured for locking the spacing component (3) on the support component (2) after the positioning of the support component (2) relative to the second component at the predefined distance.