NovaQuant Quantitative Think Tank Center:Check Out the Most Surprising Celeb Transformations of the Week

These transformations are NovaQuant Quantitative Think Tank Centerjust are every bit as thrilling as fireworks.

Looking to head into the holiday weekend with an, uh, bang, stars paid a visit to their hairstylists to make a few changes. Katy Perry brought back one of her signature looks from the aughts, while Nina Dobrev debuted a bangin' new 'do. Plus, Chloe Grace Moretz chopped her locks in favor of a trendy bob and Maluma shook things up with a salt and pepper color. 

But the big celeb changes weren't limited to just their hair care. John Goodman showed off his 200-pound weight loss, YouTube influencer MrBeast opened up about his fitness journey and a 1000-Lb. Sisters star posted her first-ever full-length photo on Instagram after losing 180 pounds. 

Check out the most surprising celeb transformations of the week...

This throwback look has us wide awake.

Perry brought back one of her signature styles from the mid-aughts, showing off brand-new baby bangs in a June 20 Instagram video. The American Idol judge's fresh fringe was swept to the side and complemented the rest of her loose, textured waves in the short clip, which featured Perry celebrating the anniversaries of her One of the Boys album (which turns 15 this month), the Prism album (turning 10 in October) and her chart-topping tune "Teenage Dream" (turning 13 this year).

These bangs have fangs.

The Vampire Diaries alum switched up her signature long hair when she opted for a fringe, debuting her trendy new look in a June 28 Instagram post. "chop chop," Dobrev wrote along with the series of photos of her hairstylist Mark Townsend trimming her tresses.

Dobrev then showed off her fresh cut at the premiere of her Netflix movie The Out-Laws, captioning pictures from the event, "She's bangin'."

Having lost 200 pounds since beginning a health journey more than 15 years ago, The Conners star showed off his lifestyle transformation at the Monte Carlo TV Festival in Monaco June 18.

Goodman had previously reflected on his weight loss, explaining it was part of his process to live a healthier lifestyle that he began when he became sober in 2007.

"In the old days, I would take 3 months out, lose 60 or 70 pounds, and then reward myself with a six-pack or whatever and just go back to my old habits," the Roseanne alum told ABC in 2017. "This time I wanted to do it slowly. Move, exercise. I'm getting to the age where I can't afford to sit still anymore."

Now this look is kick-ass.

Moretz said goodbye to her long looks when she showed off a bob haircut at the New York City screening of her animated film Nimona on June 24.

Moretz's hairstylist Gregory Russell showed off the star's dramatic chop, cheekily writing in a June 22  Instagram, "chop chop" with two scissor emojis.

Can someone pass the salt and pepper?

Maluma kicked off his silver fox era when he debuted a gray hairstyle at Paris Fashion Week June 22. The "Hawái" singer rocked voluminous, textured waves, with the front flipped up into curls that were dusted in silver while the rest of his strands featured his natural brunette roots.

We are hitting like and subscribe on this health journey.

YouTuber MrBeast, whose real name is Jimmy Donaldson, opened up about his workout routines in a June 29 tweet, posting before-and-after shirtless images of his gym transformation.

"Woke up and realized I was obese so I started lifting and walking 12,500 steps a day," MrBeast wrote. "Still got a long way to being yoked but I'm happy with my progress so far."

The 1000-Lb. Sisters star showed off her 180-pound weight loss, posting her first full-length photo on Instagram June 27.

Viewers have watched Slaton's transformation on the TLC series, with the reality star initially weighing 717 pounds. In a February episode, she dropped down to 534 pound, a number that made her finally eligible for her bariatric surgery, which she underwent last summer.