Selena Gomez watched Justin Bieber perform last night (23.03.16).

Selena Gomez

Selena Gomez

The 23-year-old singer was spotted by eagle-eyed fans at Los Angeles' Staples Center in the sound mixing area taking in her former boyfriend's 'Purpose Tour' show.

The sighting comes a few days after Justin shared a throwback photo of himself kissing Selena, who he had an on/off relationship with from 2011 to 2014, on Instagram.

He captioned it simply: "Feels"

Not only did Selena like the picture, she also commented "perfect".

The 21-year-old singer - who has most recently been romantically linked with model Hailey Baldwin - previously admitted he and his former girlfriend are always there for one another, though they don't have a lot of contact.

He said: "We don't talk often, but we're cordial. If she needs something, I'm there for her. If I need something, she's there for me."

Meanwhile, Selena recently vowed never to date the 'What Do You Mean' singer again.

She said: "At first I didn't care. To me it was: I'm 18, I have a boyfriend, we look cute together, we like that. Then I got my heart broken and I cared. Because people had no idea what was going on, but everywhere it was a million different things. I was kind of in a corner, banging my head against the wall. I didn't know where to go."

About the constant references made about Justin in the media, she added: "I'm so exhausted. I honestly am so done. I care about his health and well-being. But I can't do it anymore."