Jay-Z and Beyonce Knowles.

Will Beyonce Knowles and Lady Gaga join forces?

They have used Twitter and other social media to drop hints of a new collaboration.

The pair - who appeared together on 2009 hit 'Telephone' and extended version 'Video Phone' - have fuelled rumors they have returned to the studio by posting pictures of them wearing similar earrings.

In November, Gaga posted a photograph on Instagram of a pair of earrings engraved with the word 'Ratchet', while in December, Beyonce posted two photos of similar pieces of jewelry.

On December 29, Beyonce posted a photo of the bamboo earrings alongside a pair of purple printed flat shoes, and followed it up the next day with another image of herself wearing the earrings.

It is thought they refer to a track called 'Ratchet', which is also set to include rapper Azealia Banks, and may be released later this month as the lead single from Gaga's new album, 'ARTPOP'.

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Azealia said in September: ''I worked with Lady Gaga, but I worked with Lady Gaga from afar. We worked via email and via Internet. We have a song called 'Red Flame' and a song called 'Ratchet,' but I don't know what she's doing with it. She's going to release it when she wants to release it.''

In October, Gaga confirmed plans to record with Beyonce again.

Asked in a Twitter chat if 'ARTPOP' would feature a sequel to 'Telephone', she replied: ''Fact''.

© Bang Showbiz