Jessica Simpson's Sizzling Transformation: Before and After Photos

Jessica Simpson has always captured fans' hearts with her "Irresistible" charm!

In March 2000, the singer-actress stole the spotlight at the premiere of Here on Earth in a form-fitting slip dress that traced her slim figure.

Fashion icon? The That '70s Show alum sported a white tank top and blue low-rise jeans with a pink belt while promoting her self-titled album in July 2000.

Simpson looked like a goddess in a strapless light blue and pink gown at the Metropolitan Museum of Art exhibit of Jacqueline Kennedy: The White House Years.

The Newlyweds: Nick and Jessica star unleashed her rock star side at the Z-100 Zootopia concert. Her ensemble featured a white cropped top with a black grid-like design and matching pants that cinched at the waist. She completed the look with white gloves and white pointed-toe shoes.

Simpson lit up the grand opening of Britney Spears' restaurant in New York City when she attended the special event in a patterned, strapless dress with a fitted bodice and a sweetheart neckline.

For a 2003 event in Hollywood, Calif., the "I Wanna Love You Forever" songstress opted to rock a cleavage-baring look consisting of a black, fitted dress with a square neckline and long sleeves.

Simpson turned heads at the MTV Movie Awards as she flaunted her beauty in a pale blue flowing dress with thin straps.

Simpson arrived at a benefit concert in 2004, wearing a dazzling gold sequined gown with a plunging neckline that emphasized her voluptuous assets. The outfit also boasted a high slit, giving a peek of the songstress' flawless legs.

The former Fashion Star judge glowed at the People's Choice Awards in a black patterned dress she paired with open-toed high heels.

Simpson stunned backstage at the 2005 MTV Movie Awards, putting her slim physique on full display in a sleeveless dress with a V-neckline. She completed the look with black heels.

Looking radiant in red, Simpson posed for the cameras at the 32nd People's Choice Awards while holding a trophy after winning the Favorite Song From a Movie award.

Simpson showed off her confidence at the Teen Choice Awards 2006 by playfully striking poses while wearing a light-colored, sleeveless dress with a flared skirt and a fitted bodice.

In 2007, Simpson turned up the glam in an all-black ensemble when she attended Sony & BMG's Post-Grammy Party at the Beverly Hills Hotel in Los Angeles, Calif.

In December 2008, Simpson held her fragrance product launch at Macy's South Coast Plaza in California. She sparkled at the event in an eye-catching red dress, black cardigan and black high heels.

Looking as charming as ever, Simpson attended an event in New York City in a black, knee-length dress.

The "Savage" singer ditched her usual plain dresses and opted for a one-shoulder gown with a floral pattern at the 2010 Operation Smile Annual Gala.

Simpson made an appearance at the Us Weekly Hot Hollywood Party in a short, fitted dress that embraced her eye-popping physique.

A very pregnant Simpson attended the NBCUniversal Press Tour All-Star Party in a sparkly knee-length dress and black pumps.

Simpson put on a jaw-dropping display in a yellow dress during the 11th Annual Stuart House Benefit event.

During the Los Angeles premiere of The Hunger Games: Mockingjay - Part 1, the "Blame Me" hitmaker commanded attention in a one-shoulder gown with a high slit that displayed her toned leg.

Simpson dared to bare during the celebration of her fashion brand's 10th anniversary, leaving everyone in awe of her beauty in a black jumpsuit with a mesh neckline that subtly exposed her chest.

Simpson flaunted her enviable figure in the most elegant way at the YMA Fashion Scholarship Fund Geoffrey Beene National Scholarship Awards Gala. At the 2016 event, she flaunted her natural beauty as she posed in a black lace dress.

In 2017, the "I Think I'm in Love with You" singer brought the heat in the streets of New York City in a sultry blouse, high-waisted red skirt and high-heeled sandals.

Simpson wore a yellow day dress and platform heels to the 2018 Outstanding Mother Awards in New York City.

After her 100-pound weight-loss, Simpson cranked up the glamour in a black mini-dress with a cleavage-baring neckline and long sleeves. It boasted a thigh-high slit that displayed her legs and black stockings.

Simpson brought the heat to Jimmy Kimmel Live! in a snakeskin-print jumpsuit in 2020.

Joining Barnes & Noble's Open Book event, the Employee of the Month actress owned the look, which comprised a black long-sleeved top and high-waisted pants.

Simpson was a true fashionista as she smiled and waved at the cameras in Thousand Oaks, Calif., wearing a red leather jacket, jeans and animal-print platform boots.

Simpson was indeed the face of the night at the 2023 Footwear News Achievement Awards, outshining everyone with her beauty and glamour in a sheer silver gown that showcased her curves.

In February 2024, Simpson attended Dolly Parton's Pet Gala wearing a sparkly yellow minidress that embraced her figure. She complemented the ensemble with matching heels.

Simpson was bold and beautiful at the 2025 MTV Video Music Awards, where she shocked everyone with her unrecognizable look in a dramatic Christian Siriano gown she paired with silver earrings and pumps.