Malala Yousafzai has been campaigning for women's rights since she was a child, but it wasn't until she heard Emma Watson's powerful UN speech that she decided she would label herself a feminist.

The young Pakistani activist left the 25-year-old Harry Potter star flabbergasted when she revealed it was Emma's passionate defence of the word that converted her.

Emma, a Goodwill Ambassador for UN Women, was interviewing the 18-year-old at the premiere of her upcoming documentary film He Named Me Malala.

“This word feminism has been a very tricky word,” Malala tells Emma. “And when I heard it the first time I hesitated in saying 'Am I a feminist or not?' and then after hearing your speech when you said, 'If not now, when? If not me, who?' I decided that there's nothing wrong with calling yourself a feminist ... because feminism is another word for equality.”

“Wow, I'm so moved to hear that, that's so amazing,” Emma replies.

Malala was 15-years-old when she was shot in the head by Taliban gunmen who objected to her going to school. She was flown to Birmingham for intensive rehabilitation and has remained in the city with her family.

The documentary charts her incredible journey from being a schoolgirl in the Swat Valley, campaigning for girls to have access to education, to becoming the youngest ever Nobel Prize laureate.

Emma posted the video of their chat on Facebook, explaining that she had originally intended not to bring up the F-word with Malala and was “utterly shocked” when Malala brought it up herself.

She adds: “We are all moving towards the same goal. Let's not make it scary to say you're a feminist. I want to make it a welcoming and inclusive movement. Let's join our hands and move together so we can make real change. Malala and I are pretty serious about it but we need you.”

Watch the pair's chat:

Malala Yousafzai tells Emma Watson: “You made me believe in feminism”