Pregnant Christina Aguilera Collapsed Backstage

Christina Aguilera was ordered to cancel two of her world tour dates after collapsing backstage.

The 'Dirrty' singer, who is reported to be four months pregnant, suffered breathing difficulties during a performance in Melbourne, Australia, last Friday (27.07.07).

Although she managed to finish the concert, the star was forced to miss some songs and her encore.

Doctors were called to the venue and after treating Christina they ordered her to cancel her two remaining Melbourne dates and confined her to bed rest.

Christina - who has yet to confirm the pregnancy herself - apologized to her fans, saying she was suffering from flu.

She said: "I want to personally apologize to all of my fans.

"I am truly disappointed that I won't be able to share my show with you all."