When asked if the famous sisters have "enhanced" their infamously curvy bottoms in any way, Cheban was quick to shut down the rumor.
"I mean, I don't believe so," he told host Keith Lemon. "I don't believe the speculation. They look real to me."
See photos of Jonathan Cheban:
Jonathan Cheban out and about
Jonathan Cheban out and about
LONDON, ENGLAND - MAY 24: Jonathan Cheban speaks at the Build LDN event at AOL on May 24, 2017 in London, England. (Photo by Nicky J Sims/Getty Images)
NEW YORK, NY - MAY 15: Jonathan Cheban seen out in Manhattan for NY Pizza on May 15, 2017 in New York City. (Photo by Robert Kamau/GC Images)
LOS ANGELES, CA - MAY 10: Jonathan Cheban is seen on May 10, 2017 in Los Angeles, California. (Photo by gotpap/Bauer-Griffin/GC Images)
NEW YORK, NY - MAY 15: Jonathan Cheban, Kim Kardashian and Khloe Kardashian film inside of Joe's Pizza on May 15, 2017 in New York City. (Photo by Gotham/GC Images)
LOS ANGELES, CA - MAY 09: Jonathan Cheban is seen on May 09, 2017 in Los Angeles, California. (Photo by PG/Bauer-Griffin/GC Images)
NEW YORK, NY - MARCH 07: Jonathan Cheban attends a toast to Michele Promaulayko, the new Editor-In-Chief of Cosmopolitan, on March 7, 2017 in New York City. (Photo by Astrid Stawiarz/Getty Images for Cosmopolitan)
NEW YORK, NY - FEBRUARY 01: (L to R) Saint West and Jonathan Cheban Midtown Manhattan on February 1, 2017 in New York City. (Photo by Raymond Hall/GC Images)
LONDON, ENGLAND - JANUARY 12: Jonathan Cheban attends the Denver Nuggets v Indiana Pacers game during NBA Global Games London 2017 at The O2 Arena on January 12, 2017 in London, England. (Photo by David M. Benett/Dave Benett/Getty Images for NBA)
NEW YORK, NY - DECEMBER 09: Jonathan Cheban attends Z100's iHeartRadio Jingle Ball 2016 - Arrivals at Madison Square Garden on December 9, 2016 in New York City. (Photo by Jared Siskin/Patrick McMullan via Getty Images)
NEW YORK, NY - DECEMBER 07: Jonathan Cheban attends the DailyMail.com and Elite Daily holiday party at Vandal on December 7, 2016 in New York City. (Photo by Noam Galai/WireImage)
MIAMI, FL - DECEMBER 04: Jonathan Cheban attends DJ Khaled's birthday dinner hosted by Hublot at Komodo on December 4, 2016 in Miami, Florida. (Photo by Gustavo Caballero/Getty Images for Hublot)
MIAMI BEACH, FL - NOVEMBER 30: Danielle Bernstein, Jonathan Cheban, Craig Robins and Larsa Pippen at the Craig Robins, Jackie Soffer, Angelo Bonati and Rodman Primack Celebrate the Winners of the Panerai Design Miami Visionary Award at Private Residence on November 30, 2016 in Miami Beach, Florida. (Photo by Gonzalo Marroquin/Patrick McMullan via Getty Images)
MIAMI BEACH, FL - NOVEMBER 30: TheDishh.com founder Jonathan Cheban attends the DuJour Media, Gilt & JetSmarter party to kick off Art Basel at The Confidante on November 30, 2016 in Miami Beach, Florida. (Photo by Gustavo Caballero/Getty Images for DuJour)
NEW YORK, NY - NOVEMBER 21: Jonathan Cheban attends the 2016 Angel Ball at Cipriani Wall Street on November 21, 2016 in New York City. (Photo by Roy Rochlin/FilmMagic)
NEW YORK, NY - NOVEMBER 21: Jonathan Cheban, Khloe Kardashian, Simon Huck and Kourtney Kardashian attend 2016 Angel Ball hosted by Gabrielle's Angel Foundation For Cancer Research on November 21, 2016 in New York City. (Photo by Kevin Mazur/Getty Images for Gabrielle's Angel Foundation)
While the Kardashian's have been open about botox and lip fillers, they mostly laugh off the butt rumors.
"Once you start getting in the tabloids claiming you have fake body parts, then it's like, 'Okay, I made it. Now I'm really working out," Khloe explained to Redbook magazine in 2015. "Kourtney said yesterday, 'I got so happy because someone said I had butt implants.' And I was like, 'Doesn't it make you feel good?' She's like, 'I really feel good. I've got to keep it up!'"
Despite denying reports that they plumped up their backsides, Kim has admitted to getting butt injections -- for medical purposes.
In 2016, the mother of two, who suffers from psoriasis, admitted that she received cortisone shots in her butt, to treat symptoms brought on by the skin condition.
Watch What Happens Live airs tonight on Bravo at 11/10c 💋 @bravoandy
Happy Mothers Day to my sister @kourtneykardash who makes it always look so easy! I love you
Thank you to my babies for choosing me and allowing me to be your mom. You've given me a deep love I can't explain. I'm always here to teach you and protect you! Thank you for making my Mothers Day so special!
Stepping up into the MET like.... I have the best glam team! ❤️💄💋 thank you @makeupbymario @michaelsilvahair
The KKW X KYLIE collab of 4 nude lip kits with the new creme liquid formula is available now! So proud to collab with my little twin sissy! KylieCosmetics.com
Wearing Kimberly KKW X KYLIE
The restock is Live on KylieCosmetics.com KKW X KYLIE collab available now
So excited about this nudes collection #KKWxKYLIE
Well damn...... she shut shit down!!! Hands down best body ever! Shit, I have to get my shit together. If this isn't motivation, than I don't know what Is!! Keeks you really look amazing!!! 👑👑👑
Kourt looking for zero fucks to give on her 38th bday looking soooo good
Last pic. Vintage Versace. The Promise Premiere
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For U.S. Residents Only.
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I just like this pic
Come and meet me in the bathroom staaaaallllll 📸 @mertalas
Kris Jenner vibes
Detoxing with @fittea 💜 it tastes amazing and the ingredients are all natural 🍵 #ad
Should I be original and say long hair don't care?
Found this pic of @riccardotisci17 and I. I remember the first time you dressed me in Givenchy. So many amazing memories. I can't wait to see what's next! ❤️💋
I just like this pic
I love working out in my @waistgangsociety shaper by @premadonna87 it gives me the extra boost that I need in the gym & keeps my waist snatched.. go order yours now from #whatsawaist.com using my Discount code (Kimk) #ad
Kim x Ky Take Costa Rica 🇨🇷
Don't go chasing waterfalls 💦🌿
🌿💦 JUMP 🌿💦
Thank you @cosmesurge for saving my skin! #JetLagProblems #PsoriasisProblems