Gwen Stefani Flashes Bra on Her Birthday

Credit: Martin Karius/; LUCAS/

She may have celebrated her 42nd birthday on Monday, but that didn't stop Gwen Stefani from stepping out in a sexy sheer top that was totally open on the sides, revealing a white bra underneath.

The mom-of-two paired the racy blouse with slim black pants, plus peep-toe pumps, oversized sunglasses and hot pink lipstick.

Stefani and her older son Kingston Rossdale, 5, recently had a playdate with part of Angelina Jolie's brood at the singer-songwriter's London home.