The singer is currently pregnant with twins and she and husband Nick Cannon are sparing no expense in making the babies' surroundings as comfortable as possible.

A source said: 'Mariah and Nick have converted a whole wing of their Beverly Hills house into a luxury nursery.

'Mariah wanted 18-carat gold trim with ivory walls, soft furnishings and walk-in wardrobes full of Petit Tresor designer clothes.

'There's a top-of-the-range sound system and they'll each have diamond-encrusted iPods and a flatscreen TV that comes down from the ceiling.'

Among the items the couple have splashed out on for their son and daughter are Chelsea sleigh cribs costing $2,200 each and a Clara changing table, which has a price tag of $2800, while the nursery will also be furnished with $2,270 Glam Glider chairs for Mariah and Nick ' and a $1 million sofa.

The source added to Now magazine: 'Mariah and her designer Kenneth Bordewick are overseeing every detail.

'There's a $1 million red-crushed velvet, 24-carat gold and onyx sofa used for Michael Jackson's shows. It's very 'Alice in Wonderland' with swags on the back.

't might seem over the top, but Mariah has waited a long time for her baby dreams to come true and she says the twins will be the most spoilt kids on the planet.'