Fifth Harmony, Camila Cabello, Shawn Mendes

Mendes and Cabello both attended the iHeart Radio Music Festival in Las Vegas this weekend, where the 17-year-old Canadian singer photobombed his girlfriend on the red carpet. Additionally, the 18-year-old songstress posted an Instagram pic with her man which sees her "sleeping" on Shawn's shoulder.

Fifth Harmony is still going strong with Reflection’s third single, “Worth It,” featuring Kid Ink (which has peaked at No. 12 on the Hot 100). Though the song’s bouncy appeal is clear, Cabello credits their Harmonizers with making it a success. “I think it was really the fans that propelled that song,” said Cabello. “They requested it on the radio stations and they were so driven for us to have a successful song on the radio. We have a really, really passionate core group fanbase and I think they just worked that. They were just on it.”