Natasha Bedingfield Talks Anyone But You, Serenity Songs and Writing 'Unwritten' for Her Little Brother (Exclusive)

Romantic comedies are back, and so is the beloved hit 2004 pop song "Unwritten."

Natasha Bedingfield signed her first record deal at 22 years old, and the pressure was on to prove herself in the music industry. The British singer-songwriter — who studied psychology at University of Greenwich for one year before dropping out to focus on music — sat down to compose and felt inspired by the idea that "a child is like a blank sheet of paper."

"I was trying to write a birthday present for my younger brother [Joshua] who was 14, which is why I think the song resonates with teenagers because it's really what you need to hear at that age," Bedingfield, now 42, tells PEOPLE.

"It's what I wish I heard at that age, that you don't really have to have it all figured out. It's such a stressful question everyone loves to ask you, 'What are you going to be, what are you going to do?' And it's too much to really know the answer to that at that stage. You just have to write it a day at a time," she adds.

Now, 20 years later, "Unwritten" has reached new heights after it was featured in the Shakespeare-inspired rom-com Anyone But You, starring Sydney Sweeney and Glen Powell. In the film, Bedingfield's hit song plays a pivotal role in the film as Powell's "serenity song" and multiple characters sing its memorable lyrics throughout the film.

"It really feels like Anyone But You is about 'Unwritten,' like 'Unwritten' is almost a character in the movie," she says. "My publisher and Will Gluck, the director, they were like, 'Look, it's a big moment in the movie.' So, I believed them. But when I watched the movie, I was like, 'Wow.'"

The "These Words" singer has also loved watching fans lean in to the fun on social media: "It's kind of incredible the way that it's lifting everyone up."

A rom-com lover herself, Bedingfield — whose song "Pocketful of Sunshine" was featured in the 2010 film Easy A, led by Emma Stone — says she writes about "real things" and approaches lyricism like "comedy writer."

"I use music to get to the light at the end of the tunnel," she says. "Music connects me to everything that's good and to my higher power and my higher self and to others. And so my music is very optimistic because it's chasing the light."

Despite her natural optimism in music, Bedingfield says she often enjoys listening to "sad songs" — and music that "wakes your spirit up" like Bon Iver, Damien Rice and Rage Against the Machine.

And since Powell's character's serenity song is "Unwritten" — what's Bedingfield's? If she had to chose, she says it's India.Arie's "Get It Together."

Next, Bedingfield — whose most recent album Roll with Me — plans to release new music and currently feels inspired by "who we are and the struggle of being who we are."

"It's the same kind of things, I just see different sides of those issues. Like now, I feel a lot more confident than I was 20 years ago, but I'm also more experienced," she says.

"The No. 1 lesson is to have fun," Bedingfield adds. "Don't take yourself too serious."