Happy

"Happy" by Pharrell Williams is featured on Just Dance 2015 and Just Dance Now.

Classic
The classic dancer is a man wearing the following:
 * Magenta fedora hat
 * Sunglasses
 * A yellow pullover sweater with a smiley face on it
 * A magenta shirt (underneath the sweater)
 * Blue pants
 * Magenta shoes

Sing Along
All three dancers are men wearing the following:

Lead

 * Black jacket and tie
 * Yellow glove
 * Black pants and shoes

Backup

 * Black hair
 * White vest and tie
 * Black pants
 * Black shoes

Backup Dancers
The two males that appear in the background towards the start of the song are wearing boxes on their heads. They are blue and highly detailed. They are wearing jackets.They look similar to Video Killed the Radio Star.

There are also two girls wearing pink jackets and have pineapples on their shirts. One of the girls hair is poofy and resembles the Ghostbusters sweat version. The other one looks similar to American Girl, in style of hair.

The panda makes a reappearance, however he looks different this time. He is wearing a red/yellow headband, a radio around his neck, and red sneakers.

The first backup dancer is Cain, as seen in the behind the scenes video. The second is Aurélie Sériné. The third is Alexis, and the fourth is Shirley. Then, in the left, Alexis appears again, and, at the right, Cain appears again.

Classic
The background consists of real life shots (akin to Gentleman) with some animated effects. The real life shots are mostly underneath a concrete bridge, a residential area and a pool. There are various backup dancers dancing along to the song (see above for background dancers).

Sing Along
The Sing Along background is the same as Starships' Charleston Mode's background, aside from two microphones which have been planted for the dancers.

Gold Moves
The Classic routine has 3 Gold Moves, all of which are the same, and the Sing Along has 4.

Classic
All: Clap once with both of your hands while walking to the left.

Sing Along
Gold Moves 1 and 2 (For P1 only): Straighten your shirt. Gold Move 3: The lead points to the sky and the backups push away. Gold Move 4 (For P2 and P3 only): Push away.

Community Remix
Happy is the first song to have a Community Remix. The full remix was shown at the Ubisoft live stream. Just Dance sent about 15 people the full choreography for the people to send to Just Dance so that his/her part gets featured.

The following are featured:
 * Carl and Natassia Harris
 * JennySmilez
 * MonoFreind6
 * Party2Rock
 * Dancelicious77
 * Melanie1988
 * XXJohnXX
 * Hermanitas
 * ALEXANGEL96
 * SHOWT1M3
 * MAXPOWER999
 * HappyJENNY
 * FaTCaT
 * BLUEBIRD906
 * ALIC14
 * Estrellita
 * Sammy3
 * JUSTROX
 * Mo Chocolate
 * 1MORERABBID

Captions
Happy appears in Party Master Modes. Here are the captions attributed to the dance moves:
 * Happy Pushes
 * Jump Of Joy

Trivia

 * The background was released as the teaser trailer in the video "#June9 - Just Dance".
 * This song was used for the official trailer.
 * This was the first song to be confirmed for Just Dance 2015.
 * This is one of the several songs to have multiple dancers in the background not copying the main dancer.
 * This might be a reference to the music video, where over 400 dancers dance to the song, one by one.
 * The songs features zooms and 3D views of the dancer.
 * The dancer is meant to look like Pharrell Williams. Also, a similar (or maybe the same) dancer is in Blurred Lines, which is a song that's also partially made by Pharrell.
 * The disco ball dancer's outfit is the same as the outfit of the left dancer from Get Lucky, the only difference is that his one is pink instead of gold.
 * This is the third song by Pharrell Williams in the Just Dance series, the first and second were his features in Blurred Lines and Get Lucky on Just Dance 2014.
 * This is the only song by Pharell Williams where he sings solo.
 * The background for the Sing-Along is the same as Starships (Charleston).
 * By a vote to see what new gameplay would be unveiled, this song assumingly came second to I Love It's guard dance.
 * The background of the classic version has possibly the most animated effects in the whole series.
 * This song is shortened by 1 minute and 9 seconds.
 * In the Sing-Along routine, unlike other trios, the lead dancer is the left dancer, and the backup dancers are the middle and right ones.
 * Happy is the only trio to behave like this.
 * On the PAL cover, the dancer's shirt is shinier than in the game.
 * The backup choir is inspired from some scenes in the music video.
 * Ubisoft used to tease a game before its confirmation by pictures being shadows of dancers, in which a link was added with them. Clicking the link would redirect to the official Just Dance game site. Every link had a marker; the link from the teasing picture of this song had this one: ?utm_campaign=dm_9Jun2014_jd2015_e3tracktease happy ; the end of this marker made this song leaked.
 * The panda from C'mon and Timber appears in the background.
 * The sing along is the third routine in which the lead dancer has more gold moves, the first being the on stage mode of #thatPOWER, and the second being The Fox.
 * It's the second alternate mode that does this.
 * The choreography is performed by Jerky Jessy.
 * For some reason, the legs of one of the backup dancers who resembles Video Killed the Radio Star are not painted, unlike his arms.
 * A sweater for Animal Crossing: New Leaf called Happy Shirt was inspired by this song; it is one of the many JD outfits made by Wesley Enriquez.
 * The track has a VIP consisting of Richy Jackson. In the VIP, Richy does mildly different moves than in the original routine.
 * Happy 's Community Remix is the only one that does not require internet connection.
 * This is because it's built into the game's disc.
 * A few days prior to Just Dance 2015's release, the song was available on Just Dance Now for one week. It is the second song in the game series's history of appearing in Just Dance Now before launch, the first being Movement is Happiness. However, it got removed after that. It was re-added nearly 8 months later on April 17th, 2015.
 * This makes Happy the song with the longest time gap between its removal from Just Dance Now and its re-release.