In the novel by Shawn Mendes and Camila Cabello: Why is the moment right?

"They already feel like they've been together for much longer," said a source to E! New. "They've known each other for a while, so it's all natural and moving fast."

"The timing was not right before but it is the case now," says the insider. "They go there without restraint – this step in their relationship is exciting for both of them – they did not want to be separated at all – it's 24 hours a day, 7 days a week, and everyone at this point."

The source adds that even though Mendes is currently on his tour, Cabello "wants to be there and not leave him."

"Neither of them wants to be away from each other," said the insider to E! New. "She has the opportunity to be there with him and she enjoys it."

Before his relationship with Mendes, Cabello was in a relationship with Matthew Hussey. The split of the duo was announced in June. Mendes was previously linked to Hailey Bieber.