Serge Gainsbourg and Jane Birkin met on the set of "Slogan" in 1968, where they performed a duet, the first of many collaborations between the two. Serge quickly became Jane's mentor and lover, developing a passionate and creative relationship with Jane.
In 1969, Jane and Serge released the duet "Je t'aime...moi non plus". The song was originally written for Brigitte Bardot by Gainsbourg. The song was banned by radio stations in Italy, Spain, and the UK, for its sexual explicitness, wich contributed to its commercial success all over Europe.
In 1971 they had a daughter, actress Charlotte Gainsbourg. Jane already had a daughter from a previous relationship, and Serge gladly took her as if she was his own. That same year, Birkin appeared on Gainsbourg's album "Histoire de Melody Nelson".
They separated in 1980.