Selena Gomez thinks many of her social media fans ''probably don't even exist.''

The 23-year-old singer can't believe that she has amassed 31.7 million followers on Twitter and 40.5 million on Instagram, but believes some of the accounts are fake.

The 'Good For You' hitmaker said: ''I don't understand all of that sometimes. I think about things very realistically, because I feel like some of those accounts probably don't even actually exist. I also get very weird about that stuff. I'm like, 'Well, why isn't like everybody selling 40 million albums?' ''

Selena tries to ''be real'' with her fans and give them a glimpse at ''the dirty stuff and the fun stuff.''

The brunette beauty says she had ''no idea'' that newly-single Zayn Malick recently started following her on Twitter, but she added: ''Obviously I know Zayn now, so it's not like a weird thing.''

Meanwhile, the star admits she is ''very stressed'' ahead of the release of her second album.

She told BBC Radio 1's Scott Mills: ''I've been so stressed about everything from the second single to how we're going to present the album.''

While she recently teamed up with rapper A$AP Rocky on her latest track, she hasn't ''even met him'' yet.

Asked how their collaboration came about, she said: ''I just found his number through our people and I texted him and said, 'Hey, huge fan. Would you check out the song? I would love to see if you know you'd want to do anything with it.' And he loved it. So, I was totally prepared for a 'No, I'm good. Thank you.' It was so great and he changed some of the production of the song which made it better, and I let him have like full on freedom with everything. It was really fun.''