The singer and actress debuted a sexy new blonde crop as

she stepped out in New York last night.

Yummy mummy: Ashlee Simpson debuts her sexy new blonde crop as she stepped out with son Bronx Mowgli in New York

Clutching son Bronx Mowgli, who will be two years old next month, long gone was the straggly two-tone brown hair that the 26-year-old has sported recently.

In its place was a short blonde do that sexily swept across her face as she walked into a hotel after an evening out.

The style also impress rocker husband Pete Wentz, 31, who took to his Twitter page to show off his wife's daring new look.

Short and sexy: Ashlee looked pleased with her new do as she and Bronx headed into their hotel

He wrote: 'Yah fam headed out tonight stoked! Cute hair mama!'

Three days ago, just after Ashlee braved the hairdresser's scissors for her drastic new looks, he also gushed about it on the social networking site.

He wrote: 'New blonde pixie haircut is cute. Ill try and sneak a pic to post.'

Proud husband: Ashlee's other half, rocker Pete Wentz, posted a picture of her new do on his Twitter page

This is not the first time Ashlee, youngster sister of singer Jessica, has been blonde, but she has always preferred to keep her hair long.

When she burst onto the scene in 2004, she was blonde like her sister, but later that year she dyed it dark.

Early in 2005, she went blonde again, before dying it red in 2008 and last November went dark again, and has kept it that way since.

But last month, she sported a straggly mop of hair as she attended the US Open with Pete, which would prompt most women to head straight for their stylist.

Needs a good cut: Ashlee sported a straggly mop of hair at the US Open with her husband Pete Wentz last month

Light and dark: Ashlee with long blonde hair in 2007 and sporting a shiny red in August last year