Star Wars duo Natalie Portman and Hayden Christensen have been voted the movie couple with the most unconvincing on-screen chemistry.

Their romance in Star Wars: Episode II - Attack of the Clones, tops a poll which features movie pairings like Kate Beckinsale and Ben Affleck, and Andie MacDowell and Hugh Grant.

Affleck appears twice in the poll - once with Jennifer Lopez in the 2003 flop Gigli.

Despite the fact that Affleck and J-Lo were a real life couple, 17 per cent of voters said their romance failed to sparkle on the big screen.

Keira Knightley and Orlando Bloom were the highest Britons on the list - in third place, thanks to their roles in Pirates of the Caribbean.

Around one-in-eight people in the poll of 3,000 film fans thought there was too much of stiff upper lip in their romance and not enough lust.

Madonna and Italian actor Adriano Giannini are fourth for Swept Away, the 2002 box-office disaster directed by the pop superstar's husband Guy Ritchie.

Catherine Zeta Jones's on screen romance with Sir Sean Connery in the 1999 film Entrapment also failed to convince in fifth place, with 11 per cent of votes, partly because of the 39-year age difference.

Hugh Grant and US star Andie MacDowell are sixth for Four Weddings and a Funeral, while Affleck also takes seventh place with Kate Beckinsale in Pearl Harbor.

The then married couple Tom Cruise and Nicole Kidman are joint eigth, for their raunchy roles in the Stanley Kubrick film Eyes Wide Shut.

As are Heath Ledger and Jake Gyllenhaal for their part as gay lovers in the cowboy film Brokeback Mountain.

Titanic stars Leonardo DiCaprio and Kate Winslet drew three per cent of the votes in tenth.

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