Popular German film star Marika Rökk was suspected of being a Soviet spy, newly declassified records have revealed.

The actress became famous during Nazi and post-war era Germany after Nazi propaganda minister Joseph Goebbels decided Germany needed a film icon to rival Hollywood stars such as Ginger Rogers and Rita Hayworth.

But according to declassified intelligence reports, Rökk may have been part of a spy ring that worked for the KGB that passed secrets over to Moscow, and was suspected as such for more than 50 years.

She was first identified as a possible KGB agent in 1951 by west Germany's Gehlen Organisation, which was reportedly concerned by her "connections with Soviet authorities".

It is believed she was recruited as an agent by her manager, Heinz Hoffmeister, who was already working for Soviet intelligence, The Telegraph reports.

What her role was - and what information she could have passed onto Moscow - remains unclear.

Marika Rokk (Attribution: Bundesarchiv, Bild 146-2004-0061 / CC-BY-SA 3.0)

Rökk was considered to be one of Adolf Hitler's favourite actors and was rumoured to have had an affair with Goebbels.