Mariah Carey is four months pregnant

Mariah Carey is four months pregnant, it has been claimed.

The 'Hero' hitmaker – who was pictured on stage in Brazil earlier this week with an apparent baby bump – and husband Nick Cannon have allegedly told friends how "overjoyed" they are to be expecting their first child together, despite refusing to publicly confirm the happy news.

A source told RadarOnline.com: "Nick has been telling friends how excited he is to be a dad.

"Mariah has tried so hard to get pregnant. She's very excited. She wants to wait as close to full term as possible before going public with the news to her fans."

Following her show in Brazil, Mariah - who recently dropped out of her next movie, 'For Colored Girls Who Have Considered Suicide When the Rainbow Is Enuf', citing medical reasons – tweeted she had found the performance tough for "personal reasons".

She posted: "Seriously, I really do love it here, beautiful people inside and out! Tonite was tuff 4 me 4 personal reasons, but U got me thru! L4L. (sic)"

Nick has refused to be drawn on the pregnancy speculation this week, insisting it is a matter for his wife to tell her fans.

He said on his radio show: "I've said it before and I'll say it time and time again - when my wife feels like talking about whatever she wants to talk about, you will hear it directly from her."