The duo walked the red carpet arm-in-arm before presenting 'Winter Sleep' director Nuri Bilge Ceylan with the prestigious Palme d'Or at the end of the star-studded film festival.
Since Cannes onlookers have speculated that the pair’s platonic relationship may have turned romantic.
The pair have been close for years, with Tarantino directing Uma in his hit film Pulp Fiction. Thurman was also the star of the Kill Bill films.
Reportedly, Tarantino, 51, has long had a soft spot for Uma, 43, who he has referred to as his ‘muse’.
Uma recently ended her engagement with French billionaire Arpad Busson, with whom she has a 21-month-old daughter, Luna.