Movie star taking up old card game (5)
I believe the answer is:
garbo
'movie star' is the definition.
(I know that Garbo was a movie star)
'up old card game' is the wordplay.
'up' shows that the letters should be reversed in order (in down clue: letters go upwards).
'old' becomes 'o' (abbreviation).
'card game' becomes 'brag' (brag is an old card game).
'o'+'brag'='obrag'
'obrag' in reverse letter order is 'GARBO'.
'taking' is the link.
(Other definitions for garbo that I've seen before include "Swedish actress born Greta Gustafsson" , "Reclusive film star" , "film-star" , "Swedish-born actress" , "Old film actress" .)