Rapper Jay-Z and his wife, singer Beyonce, attend the match between Novak Djokovic of Serbia and Rafael Nadal of Spain in the men's final of the U.S. Open tennis tournament in New York, September 12, 2011.[Photo/Agencies]

Beyonce Knowles and Jay-Z may buy Ricky Martin's Miami Beach mansion.

The superstar couple - who are expecting their first child - went house hunting in Florida last week where they viewed Ricky's $12.5 million, ocean-front mansion with an estate agent although it is unclear if they will make an offer, according to gossip website TMZ.

The seven bedroom, 10 bathroom palatial home also includes a swimming pool and was originally bought by Ricky for $10 million in 2005.

Beyonce and Jay-Z already own an apartment in New York City and are thought to be preparing a huge nursery for their little one.

A source told Us Weekly their home "will have a nursery that is 2,200 square feet".

But some of the couple's friends are not too keen about the idea of creating such a big space for their tot to play in.

The insider added: "Some people are like, 'Won't you be scared to leave your baby in that huge room?' "

Beyonce has no concerns about her forthcoming step into motherhood and she recently revealed her pregnancy is "going really well".

She explained: "It's going really well, I am so happy with everything right now.

"I am not nervous because I know it's happening at the right time. I felt I got married at the right time for me, and now we are having the baby at the right time. I feel like we didn't rush anything, and now we are being blessed with everything naturally."