Reese Witherspoon doesn't know how 'This Means War' ends.

The Oscar-winning actress - who stars alongside Chris Pine and Tom Hardy in the romantic spy comedy - admits multiple endings were shot for the final scene, meaning she does not know which of the lead actors she ends up with.

She said: "We shot endings where I could end up with Tom, or I could end up with Chris, or I could end up alone. Or I could end up with Chelsea Handler!"

The blonde beauty wears a number of vertiginous pairs of heels in the film, directed by McG, and she was shocked when Chris Pine - best known as Captain Kirk in 'Star Trek' - asked her to keep them on during a sex scene.

She told Total Film magazine: "Tom and Chris were both obsessed with my shoes. Both of them! Obsessed with me wearing high-heeled sexy shoes. I was actually doing a sex scene with Chris and he said, 'Can you keep your shoes on?' I was like, OK,'."