Dakota Johnson has fuelled rumours that she's engaged to Chris Martin by flashing a large emerald rock on her left ring finger.

In photos obtained by the New York Post's Page Six, the Fifty Shades of Grey star, 31, was snapped rocking the sparkling jewellery while talking on the phone during a shopping trip in West Hollywood last week, while dressed casually in a long coat, patterned top and sweatpants, with a black face mask and her hair tied up in a messy bun.

The fiercely private couple has been dating on and off since late 2017, and has been dogged by speculation of an imminent proposal in recent weeks, after spending months in lockdown together.

Representatives for the stars have yet to comment on the claims.

Coldplay rocker Chris, 43, previously got married to actress Gwyneth Paltrow in 2003, before they "consciously uncoupled" in 2014 and finalised their divorce in 2016. The exes share daughter Apple, 16, and son Moses, 14.