Show up with former model (6)
I believe the answer is:
Here is my best explanation:
'show up' is the definition.
(I've seen this before)
'with former model' is the subsidiary indication.
'with' says to put letters next to each other.
'former' becomes 'ex'.
'model' becomes 'pose' ('pose' can be a synonym of 'model').
'ex' put next to 'pose' is 'expose'.
(Other definitions for expose that I've seen before include "lay bare", "Uncover, expose to view", "Make visible or obvious", "hazard", "Bring to light", "Lay bare", "article on scandal?", "outing", "Disclose" and "Uncover or unmask".)