Mad Men season five premiered with flying colors on Sunday night -- and all eyes (including Don's) were on Megan and her French song, Zoo Be Zoo Be Zoo. (PHOTO: AMC / Ron Jaffe).

**Spoiler alert: This article contains plot information on the Season 5 premiere of Mad Men (episodes 1-2).**

Season five of Mad Men premiered with flying colors on Sunday night. But the real champion of the two-hour event was Megan and her French song for Don, Zoo Be Zoo Be Zoo.

Draped in a sultry (and very short) black dress, Megan (played by Jessica Pare) flawlessly delivers her birthday present (in her mother tongue, naturally) to her new husband, as their nearest and dearest watch on.

It's 1966, and Sterling Cooper Draper Pryce is still in operation. Don turns the big 4-0, and Megan's French song is the cherry on top of the surprise birthday party sundae. In the premiere, Harry and Pete trade offices, Lane keeps a picture he finds in a lost wallet (borderline creepy), Joan brings her new baby to the office, and Betty is nowhere to be seen.

Since Sunday's two-hour premiere, titled A Little Kiss, Twitter news feeds and the like have been flooding with musings about Zoo Be Zoo Be Zoo.

Oh, Mrs. Draper . . . Zoo Be Zoo Be Zoo, wrote @KamarulAnwar.

Google reports server meltdown. 2 billion people tried to search the phrase, 'zoo be zoo be zoo' #madmen, joked @summersm.

As Mad Men fans patiently wait another week for the next episode (hey, it's better than 17 months, right?), here are five things to know about Megan and her French song, Zoo Be Zoo Be Zoo.

It's actually Zou Bisou Bisou Megan's rendition of the song is based on Gillian Hill's Zou Bisou Bisou, recorded back in 1961. According to a Lionsgate press release, Hill was a British actress and pop star who was first discovered by Roger Vadim, a French film director. Hill went on to star in films like Beat Girl, and the 1966 classic Blow-Up.

Hill had no idea about Mad Men using her song According to an interview with the Daily Beast, Gillian Hill had no idea her song was going to be used in one of the most anticipated season premieres this year.

Zou Bisou Bisou was a summer smash for a 16-year-old, my first record, the summer of 1960 . . . [Mad Men] is a very classic production, she told the Daily Beast in an e-mail.

The Sophia Loren connection As pointed out by many on Twitter and the folks at Vulture (New York Magazine), Sophia Loren also recorded the song in English, as part of the soundtrack to The Millionairess. The 1960 film starred Loren and Peter Sellers, performed a rendition of the song, as part of the soundtrack to The Millionairess. The 1960 film, starring Loren and Peter Sellers, who recorded a number of tracks for the film.

It's a Yé-Yé thing The sound of Zou Bisou Bisou (or Zoo Be Zoo Be Zoo) is commonly referred to as Yé-yé, which originated from France, Quebec and Spain in the 1960s (good timing, Matthew Weiner). Yé-yé singers had the common look of full bangs, high cheekbones and long lashes, often singing about puppy love and heartbreak, the Daily Beast points out. The sound is also very similar to the American version, go-go, which was popular a decade later.

You can purchase Megan's version starting Monday Less than 24 hours after Mad Men season 5 satisfied patient fans' palettes, Lionsgate has officially released Pare's recording of the song, both digitally on iTunes and limited edition vinyl.