As reported by AOL Music, in the upcoming animated film 'Dr. Seuss' The Lorax,' Zac Efron's character, Ted, goes on an adventure to impress his crush, Audrey -- voiced by Taylor Swift. However, as rumors swirl that the co-stars have secretly struck up a real-life romance, Taylor and Zac have spoken out against the rampant speculation.

"We are not a couple," Swift insisted during a joint interview with Efron on 'The Ellen DeGeneres Show.' "He's awesome, we are not a couple though. You hear people get together when they're shooting movies. But not like animated co-stars.

"Oh my God, as we were recording our voiceovers on separate coasts, we really connected," Taylor added in jest.

Despite working on the film in separate parts of the country, Taylor and Zac did manage to find time for some one-on-one music lessons together. The country singer taught the actor how to play guitar!

"She's a great teacher," Zac gushed at the Universal CityWalk premiere of the movie. "In the past, everyone who's tried to teach me guitar starts with music theory and stuff like that. I tend to just doze off after a little while. She went straight into songs. She taught me four chords, and I'm already playing all the good campfire songs."

The co-stars put their guitar sessions to the test during the talk show appearance, singing together while strumming on their guitars for Ellen. The performance was an ode to the talk show host, set to the melody of Foster the People's 'Pumped Up Kicks.' Watch a clip of the performance below and check out Taylor and Zac in action when 'Dr. Seuss' The Lorax' opens on March 2.

Watch Taylor Swift and Zac Efron Duet on 'Ellen'

Watch 'Zac Efron Praises the 'Absolutely Wonderful' Taylor Swift'