'I do' to Keanu

Forget expensive meals and exotic holidays - if you want to propose to a girlfriend, try sitting her down in front of The Matrix.

It seems sci-fi films are the perfect way to get the other half to do something impulsive, such as say 'yes'.

They put women in the mood to take a risk, while men feel more positive, a study found.

Other types of films have different emotional effects. Violent thrillers such as The Godfather are likely to make couples feel sexy towards each other, enhancing men's generosity and women's sense of adventure.

Romantic comedies such as Love Actually leave both sexes feeling flexible and open-minded.

They are described as 'compromise films' for couples unable to agree on what they want to see and likely to enhance feelings of commitment to each other. As for horror films, men find them scary and feel vulnerable. In contrast, women tend not to take them seriously and feel uplifted.

And, for those wishing to psyche themselves up, Gladiator is the perfect thing, the Diet Coke poll of 1,000 adults found.

Psychologist Aric Sigman said: 'People can be influenced by films to the extent they are more receptive to another's point of view or even more likely to commit to a relationship.'