Faithfull, one of the most colourful personalities of London's Swinging 60s, endured homelessness, drug addiction and cancer before she passed away aged 78 in January.
As the former girlfriend of the Rolling Stones' Mick Jagger, Faithfull gained notoriety for her escapades in the era of sex, drugs and rock'n'roll, but she also released 21 solo albums, won a Grammy nomination and had a film acting career.
Faithfull had worked on the new recordings over the past year. They were inspired by her first two albums from 1965 and due to be revealed in February but plans were put on hold following her death, Decca Records said.
"Marianne lived to create and perform music – it was her driving force and she never stopped," her son Nicholas Dunbar said in a statement on Friday.
"Right up until the end she was looking forward to this release which now completes and celebrates her remarkable artistic career."
Burning Moonlight, one of the new songs, which also gives its title to the EP, was inspired by the opening line of As Tears Go By. It will be released on Friday, while the full digital EP will be released on June 6.
"It's a good time to look back," Faithfull had said after completing the project, according to Decca Records.
"It helps me to remember all the things I've done. I can't say I'm a particularly nostalgic person, but I am enjoying this period of reflection."
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