Pippa Middleton Flashes Cleavage in Plunging Red Gown

Credit: Indigo/Getty Images

How low can she go?!

Pippa Middleton, who knows a thing or two about stealing the spotlight, stepped out in her sexiest look yet.

The 28-year-old brunette attended the Boodles Boxing Ball on Saturday night in a stunning red satin "Begonia" dress with a plunging neckline from the Temperley London Autumn Winter 2011 collection. She accessorized with gold heels and a matching clutch. See more pictures of Pippa's sexy ensemble from PopSugar.

The charity event drew several British royals and celebs including Princesses Beatrice and Eugenie, Prince Harry's ex-girlfriend Chelsea Davy and former Spice Girl Geri Halliwell.

Middleton, who was escorted by her boyfriend Alex Loudon, was caught smooching the financier, 31, by the Daily Mail outside the Park Plaza Hotel in London around 4:30 a.m.