“Teen Wolf” star Tyler Posey is joining Kellie Pickler, Adrienne Bailon, Ross Mathews, Chuey Martinez and Jordan “Shorty” Johnson in the ballooning co-host stable for Fox’s “Knock-Knock Live.”

Ryan Seacrest will serve as the actual in-studio host on the surprise game show, with the aforementioned half-dozen personalities playing his eyes and ears in the field — which is primarily on doorsteps.

Other stars set to appear on the impromptu contest show include David Beckham, Justin Bieber, Ariana Grande, Florida Georgia Line, Common, Rob Gronkowski, Robin Thicke, Meghan Trainor, Rita Ora, Martha Stewart, Luke Bryan, Lea Michele, Mike Holmes and Bubba Watson.

Also Read: Tyler Posey, Adam Lambert, Raven Symone to Celebrate Matthew Shepard's Parents on Logo's 'Trailblazer Honors' (Exclusive)

“Knock-Knock Live” is produced by Simon Fuller’s XIX Entertainment and Dick Clark Productions. Fuller, Michael Herwick, Allen Shapiro, Mike Mahan, Mark Bracco, Stijn Bakkers, Nicolle Yaron and Ryan Seacrest serve as executive producers. Fuller, Seacrest, DCP and Fox are stakeholders in the format worldwide. Fuller’s business XIX Entertainment has appointed DCP to be the international distributor of the format and series.

Posey’s MTV show is currently in its fifth season, and he can next be seen in Kevin Smith’s upcoming feature comedy, “Yoga Hosers.”

“Knock-Knock Live” debuts Tuesday, July 21 at 9 p.m. ET on Fox.

22 Most Groundbreaking Reality TV Shows (Photos)

SURVIVOR
Now in its 30th season, viewers have tuned in to the reality game show in droves since 2000 to watch ordinary people physically, mentally and strategically duel with each other in order to win $1 million and the title of Sole Survivor.
CBS
AMERICAN IDOL
The first televised competition show to let viewers vote on the talent themselves, "Idol" may no longer be a ratings juggernaut, but it still proves exciting.
Fox
THE BACHELOR
Though the actual long-term success rate remains shockingly low, viewers do seem to love the idea of "the bachelor" selecting from a pool of beautiful women in order to find a wife.
ABC
PROJECT RUNWAY
Even viewers not into fashion can understand this show's appeal: a reality competition that requires its contestants to actually make something to prove they deserve to win.
Lifetime
REAL HOUSEWIVES OF ORANGE COUNTY
The originator of the "Real Housewives" brand, "RHOC" showed viewers that being rich doesn't spare people messed-up lives; oftentimes, it actually makes those messes worse.
Bravo
JON AND KATE PLUS 8
Viewers tuned in to get a glimpse of how an exceptionally large family operates, but they stayed once Jon and Kate decided to divorce.
TLC
JERSEY SHORE
The housemates show earned record ratings for MTV, due in large part to controversy of how Italian-Americans on the East Coast were portrayed.
MTV
THE OSBOURNES
At one time MTV's highest rated show, it offered a behind-the-scenes glimpse of a rock legend and his family. Viewers also tuned in to see if Ozzy was ever not stoned. (He wasn't.)
MTV
THE HILLS
Originally a spinoff of "Laguna Beach," this semi-scripted series initially followed Lauren Conrad's pursuit of a career in fashion, but slowly degenerated into a series of feuds with Heidi Montag.
MTV
THE REAL WORLD
Before it regressed to the mean, "The Real World" was one of the first reality shows to explore issues facing young adults: sex, religion, death, politics and even AIDS.
MTV
AMAZING RACE
Combining a physical reality competition with exotic locales most viewers will never get a chance to see continues to prove a winning formula.
CBS
DEADLIEST CATCH
This fishing boat-based program offers a rarity for viewers: a docu-series about a dangerous profession. Coast Guard rescue squads have frequently been a part of the show.
Discovery
BIG BROTHER
If you throw a number of volatile personalities into a room together, you can bet people will tune in to watch the explosions.
CBS
RUPAUL'S DRAG RACE
If Tyra Banks could find the world's next supermodel, why can't RuPaul do the same for drag queens?
Logo TV
PAWN STARS
It's hard to say what's more appealing: getting a dose of history in everyday artifacts that are brought in for appraisal, or the interactions of the colorful Harrison family that owns the shop.
History
AMERICAN CHOPPER
Centered on the Teutel family and their shop, the series showcased contrasting styles and verbal arguments between Paul Sr. and his son. Arguments drove ratings until Junior's dismissal from the show.
Discovery
TOP CHEF
Fans of good food love this competition show about aspiring chefs cooking their way to the prize money awarded to the winner.
Bravo
HERE COMES HONEY BOO BOO
Described as both offensive and exploitative, this spinoff of "Toddlers & Tiaras" instantly became must-see-TV and made its 6-year-old star a cultural lightning rod.
TLC
JACKASS
Who wouldn't want to watch a group of friends torture and humiliate each other? Such is the appeal of "Jackass," which spawned three (and a half) movies and an acting career for Johnny Knoxville.
MTV
KEEPING UP WITH THE KARDASHIANS
Attracting instant notoriety for a sex tape featuring its star, this Kardashian chronicle has proven to be one of the most popular reality shows of the current era.
E!
DUCK DYNASTY
Following a Louisiana family made wealthy by their duck-hunting products, the Robertsons became cultural icons for their ZZ-Top beards and frank yet cheerful outlooks.
A&E