Combining test from two fields into one

[Gilmax]

So I have a need to try and combine two text fields from my Scoreboard into a single field in my overlay with a separator between them, and only if the second field has data (ie is not null) in it.

Example:
field1_1 = George
field2_1 = Fred

Displayed on Overlay as George & Fred

field 1_2 = Harry
field_2_2 = NULL

Displayed on Overlay as Harry

Thanks in advance.