When Selena Gomez stopped by "Late Show" to chat about her latest single, "Who Says," David Letterman couldn't resist bringing up Justin Bieber's name. And while she wasn't too forthcoming with details, she did give some insight into why she cares so much for her boyfriend.

"Oh, that's cute," she said when showed a picture of the teens at the Vanity Fair Oscar party last month. "It was like a little prom night, wasn't it? Looked like it."

Letterman then wondered how long she and Bieber have known one another. She said, "Almost, like, two years now." Letterman pressed further, asking how they met. "Actually, his manager called my mom, who's my manager," she explained, before Letterman joked, "I heard he was your paperboy."

"I'm blushing!" she said.

"Are you dating or not dating?" Letterman asked again, and Selena danced around the answer. "He's been in my life for so long, and it's just nice to have someone that understands what you're going through."

"This is not my first rodeo, you can talk to me about these things," Letterman quipped as she laughed. Then he promised not to go any further in his Bieber-related questioning.

Both stars have been as quiet as possible about the true nature of their relationship, though they have been spotted out on dates together. Earlier this month, Gomez was by Bieber's side as he celebrated his 17th birthday. And while on tour abroad, Bieber tweeted a message to her, noting how much he missed her.