Taylor Swift and Zac Efron addressed dating rumors on a recent episode of Ellen. The Lorax co-stars also treated viewers with an impromptu guitar duet. (PHOTO: Screen Capture / YouTube / Warner Bros).

Taylor Swift and Zac Efron have a bone to pick with those dating rumors.

The two paid a visit to The Ellen DeGeneres Show to promote their upcoming film, The Lorax. But all eyes and ears were on those dating rumors, as DeGeneres wasted no time on the show, airing Tuesday.

You're just such a cute couple, DeGeneres said to Swift, 22, and Efron, 24.

We're not though, Swift interjected.

DeGeneres had fun with the pair, addressing everything from Efron's rock hard abs to their (separate) Valentine's Day plans.

We are not a couple . . . he's awesome, we are not a couple though. You hear people get together when they're shooting movies, co-stars. But not like animated movie co-stars. You know what I'm saying? Like oh my God. When we were recording our voiceovers on separate coasts, we really connected, Swift joked later in the interview.

Efron and Swift, who voice the characters Ted and Audrey (coincidentally, love interests) in The Lorax, also treated the Ellen audience to an impromptu guitar performance of Foster The People's Pumped Up Kicks.

Zac wanted to show you how he learned how to play guitar. I taught him how to play guitar. He's really good at it for like, one lesson, Swift said.

Instead of singing Foster The People's original lyrics, Efron and Swift poked fun at DeGeneres' long work days, her sweaters, and weird interviews.

I've been on this show / eight times now and I still remember / Ellen hiding in the bathroom / with a hidden camera and she scared me so bad / and I fell and I could've died / she always asks me who I'm dating every time I'm on the show / and I don't' even know why/ but it gets five million hits on YouTube, Swift sings. (And she's not lying about those dating questions).

Meanwhile, Efron's rumored girlfriend these days is Lily Collins, who co-stars with Julia Roberts in the upcoming film Mirror Mirror. On Valentine's Day, Efron and Collins were spotted dining at Soho House in West Hollywood, according to People.

Swift's ex boyfriends have included Jake Gyllenhaal, Taylor Lautner, John Mayer and of course, Joe Jonas.

Scroll down to watch clips of Taylor Swift and Zac Efron's recent visit to The Ellen DeGeneres Show.

The Lorax opens in theaters Mar. 2.