Christina Aguilera’s pregnancy supposedly “wasn’t expected”.

Reports emerged this week that the 33-year-old singer is carrying her first child with new fiancé Matt Rutler.

She is already mother to six-year-old son Max from her previous marriage, and although having a second child is a surprise, Christina is said to be elated with the news.

"[The pregnancy] wasn't expected, but it also wasn't unwelcome,” a source told Us Weekly magazine.

“They are all very excited though! Christina loves being a mom.”

Christina and production assistant Matt are said to be tying the knot later this year.

But although the wedding is a priority, it is claimed they are focusing more on their child.

"They just want a healthy baby," the insider added.

News of the couple’s family expansion grabbed headlines just under a week after Christina announced the news of their engagement.

Apparently Matt planned his proposal down to every detail to ensure his future wife would be blown away by the experience.

"He wanted to do something that had meaning for both of them," a second source revealed, noting the proposal took place just after sunset beneath a gazebo in the backyard of their new house, which is currently under construction.

Matt supposedly wore a suit during the proposal and according to the website the pair were “surrounded by candles and hundreds of red roses”.

It is claimed Christina remains in shock over how perfect the moment was.

"She was completely taken aback. She had no idea that he was going to propose then," the insider said.

“It was a great night.”