Selena Gomez exposes her flesh-coloured underwear in a sexy cut-out dress during performance at radio event

She is known for her sweet and innocent demeanour.

But Selena Gomez was anything but in a very risque ensemble during an energetic performance at the 103.3 AMP Radio Birthday Bash concert in Boston, Massachusetts on Sunday.

Selena amazed her audience with her voice but also an expected view of her flesh-hued string underwear more than once during her set.

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Flesh tones: Selena Gomez exposed her underwear during her energetic performance at the 103.3 AMP Radio Birthday Bash concert in Boston on Sunday

The 20-year-old starlet was singing her heart out into the microphone when the front of her cut-out dress parted ways most immodestly exposing her underwear.

Selena was sexily decked out in a mustard-yellow, Moroccan-style costume with black undertones.

The fetching frock was banded at the waistline and provided generous peeks of her slender sides and back.

Exotic: The Come & Get It singer’s costume featured revealing cut-outs at the sides and back as well as a sexy slit in front

She’s got rhythm: Selena was jazzed by the crowd and gave this performance her all

Oops again: Selena’s flesh-hued underwear was showing again as her dress parted in the middle

Bouncy: Selena tossed her wild mane of brown hair around the stage as well

As in her video for Come & Get It, the entertainer let her thick dark hair fall loose and wild down her back.

Selena, who turns 21 on July 22, was looking older than her years as she danced wildly to the rhythm of the beat, her features accessorised with plenty of red lipstick.

After her show, Selena tweeted: ‘What an amazing crowd! Thank you @1033ampradio #AmpBdayBash Getting stoked for my tour!’

Loves her name: The 20-year-old star even had her name printed on her microphone in pink letters, ending it with a heart

She means business: The petite singer was a force to contend with

Sing it out: Selena belted out her tune with heart and soul

Slender: The singer’s workouts at the dance studio have paid off as she paraded her toned legs and waist before the live audience

She’s been on a whirlwind schedule but showed no sign of slowing down.

On Saturday. Selena raised temperatures in her red bra-top and high-low skirt during a pre-taped concert at Liberty State Park for Macy’s Fourth of July Fireworks Spectacular.

The Spring Breakers star flaunted her cleavage, midriff and long legs in a red-braided top and bridal-white cascading skirt.

Such a flirt: The long-haired starlet enjoyed the enthusiasm of the crowd

Natural born: Selena has what it takes to make a concert memorable

Welcome: The former Wizards Of Waverly Place star had the ability to make everyone in the crowd feel special

Selena finished off her spirited ensemble with blue eyeshadow, an iridescent microphone and white gladiator heels.

The 37th annual event will air live on NBC Thursday with performances from Selena, her BFF Taylor Swift, Tim McGraw, Mariah Carey and her husband Nick Cannon.

Gomez will officially kick off her own Stars Dance Tour on August 14 at Vancouver’s Rogers Arena.

Tour: Gomez will officially kick off her own Stars Dance Tour on August 14 at Vancouver’s Rogers Arena

Release date: Selena’s Come & Get It album, already available for presale, officially hits shelves on July 23

Her album of the same name, already available for presale, officially hits shelves on July 23.

Selena’s single Come And Get It reached the top spot on the U.S. Top 40 and she released a short YouTube video on Monday capturing her reaction and thanking her fans.

The single star split up with Justin Bieber earlier this year.

She has confirmed she is ‘absolutely available in every way’ and in fact spent last Wednesday hanging out with singer Austin Mahone at Disneyland.