Mad Men Finale Coke Ad: Twitter Needs to Know Who Wrote It

May 18, 2015 7:36 AM EDT

The closing song in the Mad Men finale Sunday night was the famous Coca-Cola jingle “I’d Like to Buy The World A Coke,” but Twitter is trying desperately to figure out who the “I” is.

Is it Don or Peggy?

Some people thought that Don’s trip to the hippie retreat wasn’t enough for him to escape his true calling as an ad man, inspiring him to come up with the Coke pitch:

No trip to hippie seminar is wasted. Go, Don! #MadMenFinale
— David Corn (@DavidCornDC) May 18, 2015

#MadMenFinale don went back to nyc, took cocacola as Peggy noted + used CA time as inspiration. final scene was his pitch! #brilliantfinale
— Shelly Puri (@shellypuri) May 18, 2015

So "ding", Don gets an idea and goes back to make the Coke Ad? #MadMadFinale pic.twitter.com/80hBAl5olg
— David Clinch (@DavidClinchNews) May 18, 2015

But others thought it was Peggy who came up with the song while Don sheds his identity as a Mad Man in California:

And after Peggy wrote that famous Coca Cola ad, years later she went on to master mind this: http://t.co/lrsCNlaNMg #MadMenFinale
— dbcsg (@dbcsg) May 18, 2015

Or maybe it was both of them working together:

I'm getting closure by imagining Don became zen at the retreat, went back to NYC and co-wrote the Coca-Cola ad with Peggy. #MadMenFinale
— Brando (@frenchhissing) May 18, 2015

Don calls Peggy with the idea for the @CocaCola ad and she writes the script. His only catch, girl with braids #MadMenFinale @MadMen_AMC
— Christy Belden (@christy_belden) May 18, 2015

In real life, of course, the song was actually the brainchild of a man named Bill Backer, a creative director at McCann-Erickson. But getting in on the social debate Sunday night, even Coca-Cola thought it was Don: