Alessandra Ambrosio ''wanted to scream'' when she was asked to model the Fantasy Bra at the Victoria's Secret Fashion Show.

The Brazilian beauty was delighted to be chosen to wear the prestigious jewel-encrusted piece - which is redesigned every year - for the 2012 catwalk spectacular.

She said: ''I just wanted to scream. But I won't lie, I was really worried.''

This year, the Fantasy Bra takes a floral theme and the $2.5 million design by Long Island's London Jewellers features a centrepiece of a 20 carat white diamond, and 5,200 other gems including amethysts, sapphires, rubies and diamonds set in 18-carat rose and yellow gold.

Alessandra said: ''It was perfect - I felt they made it for me. It's very romantic.

''I'm pretty calm. I've been waiting for this moment for a long time.''

The 31-year-old model heard the news in May, when her son Noah was just three weeks old, and got to work shedding her baby weight in preparation as soon as possible.

She said: ''I was playing a lot of volleyball on the beach, swimming and running after my kids. And breastfeeding always helps!''

The 2012 Victoria's Secret Fashion Show is set to take place on November 7 and will feature performances from Rihanna, Justin Bieber and Bruno Mars.

Previous Angels to have donned the Fantasy Bra include Miranda Kerr, Gisele Bundchen and Heidi Klum.