In the early months of 2019, Cabello and Mendes released their summer anthem Señorita which topped US Billboard Hot 100, won an American Music Award(AMA), two MTV Video Music Awards (VMAs), a People's Choice Award, and a nomination for Grammy Award for Best Pop Duo/Group Performance. At the time, the duo hasn't confirmed their relationship. But many of their fans have speculated otherwise.

Few months after Señorita's release, photos of Cabello and Mendes spending holidays together surfaced on the Internet. Entertainment news agency E! confirmed that the two are dating. "It already feels to them like they've been together for a lot longer than they have," a source disclosed. "They've known each other and been a part of each other's lives for a while so it's all very natural and moving quickly."

When Mendes' fans first heard his song Treat You Better, most of them knew that this track is specially written for Cabello. This was later confirmed by the artist in a snippet from his Netflix documentary In Wonder.

"For the past four years, just being friends and not see each other very often, to finally being able to be together, she was always there to look out for me as a human being. She's got my back, and I think that's what your partner's for; we're in New York, and my song comes on the radio and the fact comes up that it's about her. And I'm like 'Yeah, it's about you.' Everything's about you. They've always been about you. She goes 'What do you mean?' I'm like 'They're all about you, like every song I've ever written," said Mendes. 

"And I'm rhyming off the songs like Treat You Better, all these songs. She's like 'Oh my God!" She literally had no idea. This whole time I thought she knew," he added.

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When Mendes admitted to writing hit music that is inspired by Cabello, it is not surprising that every lyric in his song Wonder is also about his girlfriend. Wonder is a euphoric anthem about Mendes' thoughts on life and relationships. 

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The pair wrote I Know What You Did Last Summer as a song evoking the styles of their favourite artists like John Mayer and Ed Sheeran. According to Cabello, to soulful pop duet stemmed from her real-life heartbreak.

“At the time, I was talking to a guy that I liked, and a friend called me two days before we wrote the song and told me he had been hitting her up and trying to flirt with her as well,” Cabello told Rolling Stone. “[Shawn and I] started talking about that in the song. It’s about finding out that somebody had been cheating on you, and the song is that moment right before you confront that person where you both know what’s next, but it’s killing both of you."

The moment Cabello released All These Years, many of her fans guessed that the track is about Mendes. The song is about Cabello bumping into an old love interest and all of her old feelings flooding back.

The two have been seeing each other as early as 2015 in awards shows when Cabello was still part of Fifth Harmony.

In his song Lost In Japan, Mendes dreams of an off-country getaway with a friend or a romantic interest. For years, he and Cabello were firm in saying that they are just friends, the song Lost In Japan suggests that both of them have taken it to the next level. 

A month before its release, Cabello was also spotted in Japan for a press trip. Coincidence? We don't think so. 

Cabello bared it all in her track called Shameless. In a Facebook live interview, the artist said that the song hits different for it mirrors her thoughts on being madly in love. "I love Shameless just 'cause I feel like it's the way that I wanna love. Like shamelessly, and fully and unabashedly," she said. 

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