During a segment of The Late Late Show on Wednesday night, the 40-year-old host wakes up at 2:25 a.m. to join in on Wahlberg's infamous 4 a.m. exercise routine. Corden is understandably disoriented and angry after waking up in the middle of the night, admitting, "I'm praying that he cancels."
The 47-year-old actor doesn't cancel, and so Corden heads over to his house about an hour after getting out of bed. "I've never seen these roads so quiet," he marvels during his drive.
"This is ridiculous. This is the most ridiculous thing," Corden tells Wahlberg when he enters his home gym. "Why are we doing this?... I saw one car on the journey here!"
"Isn't it nice and peaceful, though, when you get up [early]?" Wahlberg replies.
"I was more peaceful when I was flat out asleep," Corden quips. "I was completely peaceful."
After some stretching, Corden looks over Wahlberg's busy daily schedule, which begins at 2:30 a.m. and includes two breakfasts -- something Corden is very keen on.
As for why Wahlberg is so dedicated, it all comes down to his kids: Ella, 15, Michael, 12, Brendan, 10, and Grace, 8.
"When the girls get older the boys start coming over, ringing the bell. You gotta be ready!" Wahlberg exclaims. "There's a whole other fight in front of you."
Corden doesn't seemed as concerned for his children -- Max, 7, Carey, 4, and Charlotte, 11 months -- declaring that he'll just say, "I know Mark Wahlberg."
"So don't mess with me because I'll call him and he'll come over, provided it's before 5 p.m. Otherwise, he'll be asleep," Corden adds.
The workout finally kicks into gear with weight lifting, running on a treadmill, push ups and other high-energy activities. During some jumping lunges, Corden states, "Now I feel like we're in a boy band and I'm enjoying it." He then begins to sing "Everybody" by Backstreet Boys.
After showing off a couple of themed T-shirts, Corden realizes that the seemingly strenuous workout he just completed was "just the warm-up" and decides to call it quits.
"Just make sure he doesn't throw up in my bathroom," Wahlberg quips after Corden leaves the room.
Corden isn't the first celebrity to join Wahlberg's early morning workout club! ET's Nischelle Turner caught up with the actor last month where he recalled when his Instant Family co-star, Octavia Spencer, participated.
"I got phone calls from some of the biggest stars in town, like, 'I'm coming to the 4 a.m. club. I aspire to be better.' Nobody showed up," Wahlberg said. "She comes in and she kills it. You know what? She's inspiring so many other people."
Watch the video below for more on Wahlberg's workouts: