John Cena and Shaq belt out Cena's iconic theme song "My Time Is Now" during their time in the car on Apple Music's "Carpool Karaoke."

The time is now for John Cena and Shaquille O'Neal ... to sing some karaoke!

Yes, Cena and Shaq's long-awaited appearance on Apple Music's "Carpool Karaoke" will air on Tuesday, Sept. 5. The two stars will sing such hits as LL Cool J's "Mama Said Knock You Out" and Cena's own theme song, "My Time Is Now."

One large man. One much larger man. Sweet, sweet music. @carpoolkaraoke @Shaq pic.twitter.com/qKdas0btwR

— John Cena (@JohnCena) August 30, 2017

Check out the preview clips, and be sure to tune in on Tuesday, Sept. 5, on Apple Music to see what other hijinks these two get into on the road!

John Cena and Shaquille O'Neal lend their voices to LL Cool J's iconic track, "Mamma Said Knock You Out," on Apple Music's "Carpool Karaoke."