The 28-year-old, who has been dating actor Adam Shulman for three years, thinks people can fall for each other as soon as they meet.
Asked if she believes in love at first sight, Hathaway said: 'Why not?
'I think its a good thing to believe in, I think it'd be a shame if we didn’t have that, it’d be a lot less fun.'
Hathaway also thinks people can have a 'soul mate' for the rest of their lives.
Speaking at her One Day premiere in New York City last night, Hathaway added to HollywoodLife.com: 'I think there's a lot of people out there but I think usually there's one person out there that you can find yourself committing to.'