You better Believe it – it's looking like superstar singer and actress Cher will headline Sydney's 40th gay and lesbian Mardi Gras in March.

While it is understood a contract is yet to be signed, sources close to the event have told Fairfax Media the 71-year-old gay icon is almost locked in to perform at the world-renowned gay pride festival.

Organisers typically seek out big overseas acts on major anniversaries – the 30th Mardi Gras was headlined by Cyndi Lauper – and this year's will take on extra significance given the historic legalisation of same-sex marriage just weeks ago.

The rumour mill has been in overdrive, especially after the If I Could Turn Back Time singer hinted at the deal on her official (and ever zany) Twitter account, teasingly posting: "Where am I going in March!?"