The former lovers were spotted by an eagle eyed fan at Ed Sheeran's concert at Staples Center in Los Angeles on Saturday night.
Perry was recently spotted having an intimate dinner with Robert Pattinson at a West Hollywood Hotel but she has now turned her attention to her previous love.
The pair both wore baseball caps and dressed low key but they seemed very happy to be in one another's company once again at the concert.
At one point Perry, 32, appeared to lean back into Bloom, 40, in a photograph posted on Instagram. The stars had floor seats for the sold out show.
An eye-witness revealed: "They definitely seemed like they were back together – they cuddled most of the night. She sat on his lap and they shared kisses.
"They looked like they were having the time of their lives – people didn't really bug her. I don't really think people knew it was them because they had hats on and stuff."
It is not known if the pair arrived at the concert together or privately.
The couple started dating at the start of 2016 before splitting up in March 2017, although they have remained friends.
They made headlines all over the world when Bloom infamously stripped naked on a paddleboard with her in Italy.
And now it looks like their relationship could be heating up once again.
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