Dressed in a plunging white top, the 24-year-old star was spotted in the sound booth inside Ziggo Dome, rocking out to The Weeknd's tunes and sipping on a drink, reported HollywoodLife.
"Abel (Makkonen Tesfaye, known professionally as The Weeknd) even wants Sel to come on stage with him, even if it's just for one short song. He thinks Sel is incredibly talented and it would be a total thrill to have her on stage.
"Honestly it probably won't happen as she's happier just letting him do his thing," a source said.
The couple first stepped out publicly together in early January this year, where they were photographed cuddling.