Dannii Minogue worries that she's not "compatible" with her ex.

The Australian star split from model Kris Smith in April this year. The pair - who have 23-month-old son Ethan together - sparked rumours of a reconciliation recently when they were spotted together.

Although they're not officially back together, a source close to Dannii says she remains hopeful.

"One week, the pair are talking about their future, and the next Kris is saying Dannii is putting him under pressure," an insider told British magazine Closer.

"She worries they're not compatible, but she'd love to be a mum again."

Dannii is also said to be finding it hard seeing her fellow Australia's Got Talent judge Brian McFadden loved up with his fiance Vogue Williams. The star craves her own happy ending.

"Dannii says Brian and Vogue are all over each other - she's happy for them but says it makes her miss being in a relationship," the source added.