Are Katy Perry and Robert Ackroyd Back On?

Though they officially split two weeks ago, Katy Perry gave Florence and the Machine's Robert Ackroyd the V.I.P. treatment during the Summertime Ball at Wembley Stadium Saturday.

"Katy made sure Rob could roam around freely backstage and do as he pleased. She also gave him a list for five guests to attend," a source tells Us Weekly. "Rob was in the pit with his friends for her set but was singing the wrong words! It was quite funny but very sweet."

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Adds the source, "Katy made a real fuss over him and made sure he was well looked after."

This is the second time the pair have hung out this week; on Thursday night, Ackroyd met up with the "Part of Me" singer following her Graham Norton Show taping.

Perry, 27, and the musician first went public with their fling at Coachella in March; in late May, a source told Us they had decided to part ways.

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"It wasn't that serious," the insider revealed. "It's not a nasty thing and they are still talking, but Katy told him to do his thing . . . No hard feelings. She's really busy and so is he."

During her Thursday chat with Graham Norton, Perry opened up about struggling to put on a happy face while on tour -- even as her 14-month marriage to Russell Brand was unraveling.

"I love being onstage, and even though I went through some pretty tough times last year, I had to separate that because I know my problems are my problems and they are not the audience's problems," she explained. (Brand filed for divorce on Dec. 30, 2011 -- just weeks before the conclusion of her world tour.)

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Continued Perry, who dons over-the-top, candy-inspired costumes for her sets, "[The audience] is here to see a show and to be entertained, so I got on that lift, put a smile on my face, and went up [on stage] with my t--s spinning!"

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