Beyonc drops surprise album Lemonade ahead of world tour

Beyonc has pulled another Beyonc.

The pop superstar has dropped yet another surprise album, releasing Lemonade via streaming service Tidal on Saturday night.

Lemonade's release coincided with an hour-long HBO special of the same name and was cryptically teased on social media last weekend, building buzz that a new album was close at hand.

The HBO program featured a compilation of music videos, vignettes and vintage, home-movie-style footage, with chapters carrying titles that riffed on the grieving process stages, such as anger, denial and forgiveness. It appeared to address long-standing rumours of trouble in her marriage with rapper Jay Z.

Some videos also featured appearances by the mothers of two black men, Michael Brown and Trayvon Martin, whose shooting deaths, in Brown's case by a Missouri police officer, have shone a spotlight on U.S. racial tensions.

Lemonade is Beyonc's sixth album and her second "visual album." It features 12 tracks and a short film.

Her 2013 self-titled Beyonc was also a surprise record featuring 14 songs and 17 videos that arrived without any promotion.

Lemonade features vocals from Kendrick Lamar, Jack White, James Blake and Toronto's own the Weeknd.

The final track is Formation that gritty, catchy tune paying homage to Bey's southern roots that was released a day before the singer's powerful Super Bowl 50 performance.

The Formation music video, which features scenes from a devastated New Orleans after Hurricane Katrina, followed by the half-time show that also announced Beyonc's upcoming world tour, had her massive fan base eagerly anticipating an album.

The Formation tour kicks off in Miami next Wednesday.