Nick Cannon is reportedly a "little shocked" by Mariah Carey's engagement news.

Nick Cannon

Nick Cannon

The singer's Australian beau popped the question on Thursday (21.01.16), despite the pair having dated for less than 12 months.

Nick, who was married to Mariah from 2008 to 2014, is said to be slightly taken aback by the news considering the speed of their whirlwind romance.

A source said: "While Nick certainly supports Mariah and James' decision to get married, he's a little shocked. Surely, it was in the back of his mind that the mother of his children could tie the knot again.

"And now that it's happened, he's a little taken back by it. It always stings when your ex moves on in a major way like marrying another man."

Despite Nick's feelings, he is said to be adjusting quckly to the idea, mostly because he knows it would also be beneficial for his and Mariah's twins Moroccan and Monroe.

The source added to HollywoodLife.com: "Nick's adjusting. He knows James and knows that he's a good man and he's good with the twins."

James is said to have proposed in Mariah's hometown, with a stunning 35 carat diamond ring.

A source told E! News: "They fell head over heels in love with one another. It's crazy how perfect they are together, they both know it and couldn't be happier.

"As soon as their friendship turned romantic, they have wanted to spend every moment together. They have a connection that is unparalleled; it's been a very beautiful experience for them both. If you spend even five minutes with them, you can't help but believe in true love.

"They are just very cute together, they like doing sweet things for one another. They want to make each other happy."