Katy Perry and John Mayer have discussed starting a family together.

The on-again, off-again couple, who recently rekindled their relationship after splitting twice earlier this year, ''are definitely back on'' and eager to settle down.

A source said: ''After their last breakup in July, John realised he made a mistake letting Katy go. Katy wanted kids, and he wasn't ready, but now he's told her he's on-board.

''It's been a bumpy ride, but they're in a good place again.''

But the 37-year-old singer would prefer to make the 30-year-old 'Dark Horse' hitmaker his wife before they have a baby together.

The insider said: ''Before they have a baby, John wants to be married. Getting married isn't as important to Katy, but since it is to John, they've talked about tying the knot by next summer.''

The pair were spotted holding hands at mutual friends Allison Williams and Ricky Van Veen's wedding in Wyoming recently.

The source added to Life & Style magazine: ''Being at Allison's wedding made Katy and John realise they've got something very special. They are ready to take things to the next level.''