And though they've denied any pairing, the duo looked like they were getting very close, after grabbing a Sunday brunch in Los Angeles.
Mendes and Cabello flirted and hugged while they were joined by Mendes' sister Aaliyah and his mother Karen, during a post-brunch house-hunting endeavor in West Hollywood.
There have been romance rumors about the singers for years, though any romantic relationship has yet to be confirmed by either Mendes, 20, or Cabello, 22.
Mendes was clad in a black Nike long-sleeved shirt and black pants with white shoes, while Cabello was wearing a low-cut white top under a light black jacket, black pants and black shoes.
Shawn was either seen holding hands with Cabello, putting his arm around her as they walked, or hugging her from behind after brunch.
Mendes was enjoying an off day from his tour on Sunday, after two nights of back-to-back shows at Staples Center in Los Angeles.
He is about to head to San Diego for a show at the Pechanga Arena on Monday to continue his tour.
Both Mendes and Cabello have continued to deny rumors of their romantic relationship, with Mendes doing so at a Q&A this weekend.
Mendes was asked a two-part question by a female fan, with the first part being, 'Are you dating Camila?' with the singer shaking his head no, which fans reacted strongly to.
The second part of the question was, 'If not, will you go out with me?' which amused the singer.
'That was the best set-up to a "Will you go out with me?" I've ever heard,' Mendes said, while reaching for a mug in the video.
'I won’t [go out with you]. I don’t know you, that’s why. I need to get to know you first,' Mendes said, before taking another fan's question.
While Mendes and Cabello keep shutting down romance rumors, Cabello did post a number of videos and photos from Mendes' Los Angeles concerts.
She was in attendance for both of his Staples centers shows on Friday and Saturday night during the Los Angeles portion of his tour.