One in Red Dwarf perhaps getting a step up? (5)
I believe the answer is:
stair
'a step up?' is the definition.
(I've seen this before)
'one in red dwarf perhaps' is the wordplay.
'one' becomes 'i' (Roman numeral).
'in' indicates putting letters inside.
'red dwarf perhaps' becomes 'star' (red dwarf is a kind of star).
'i' put inside 'star' is 'STAIR'.
'getting' acts as a link.
(Other definitions for stair that I've seen before include "Component of flight" , "something of a case" , "section of flight" , "Support on which to step" , "One of a flight of steps" .)