Katy Perry has told her fans that she's helped to deliver a baby.

The Roar singer didn't go into detail about who's baby, or babies, she'd helped bring into the world.

But she tweeted to her 50 million followers: "Finally you can add 'helps delivers babies in living rooms' to my resume!

"It's been a miracle of a day... Auntie Katy aka Stylist Auntie," she wrote, sparking speculation that the baby was her older sister's.

Meanwhile, Katy did not comment on reports that she and John Mayer have split up.

The Dark Horse singer and the US singer-songwriter - who have been dating on and off since August 2012 - split a few days ago, according to E! News.

A source told US Weekly that the break-up "may be for good".

Another source told the publication that Katy's forthcoming Prismatic world tour had caused problems for the couple.

"She's stressed about the tour, they've been fighting," the source was quoted as saying.