The joyful craze started with the catchy little ditty called "Happy" that pop star Pharrell Williams wrote for Despicable Me 2.

Then came the "24 Hours of Happy" video that went viral. The day's worth of blissful boogie-ing by Williams and his celebrity friends spawned cheerful YouTube copycats all over the world, from Hong Kong to Philadelphia.

Even ABC's Good Morning America capitalized on the musical merriment - the likes of which haven't burned up Billboard since Bobby McFerrin's 1988 hit "Don't Worry Be Happy" - posting viewers' happy dances on social media with #GMAHappy.

Now, after an Andy Warhol-esque painting of the singer titled Happy went up at the Art League Gallery in Alexandria, Va., and a few tears were shed by Williams on Oprah Prime, fashion is making happy even haute-er.

On March 20 - in honor of the International Day of Happiness, of course - Miami-based sportswear company Peace Love World released a line of soft V-neck and crew Pharrell-inspired T-shirts for men, women, and children.

The graphics are delightful and include peace signs, hearts, and smiley faces topped with the Smokey Bear-style vintage Vivienne Westwood hat Williams wore to the Grammys in January.

And so everyone would know for sure that the apparel is homage to the hit song, Peace Love World's creative director Alina Villasante added quotes from the jam including: "I am Happy," and my personal favorite, "Happiness is the Truth."

"[Pharrell and I] have the same mantra in life, and that is to choose happiness," said Villasante, who counts Williams among her friends. The five-year-old company is a collection of cozy, upbeat sportswear mainly for the urban woman who has a bit of yogi in her. Other sayings in the collection include "I Love Sundays," "Let Love Bloom," and "Happiness is the new Black."

The grouping of limited-edition T's will be expanded to include cellphone covers, silicone bracelets, sweatshirts, and hoodies.

"It's unbelievable how people want these things," Villasante said. "I never expected this."

Locally, the shirts are selling well. Mona Lisa Jackson of Rittenhouse Square lingerie boutique Coeur ordered 50 of the T's in black and white, which sold out within two weeks. An additional order of 70 is set to arrive any day.

"They just make people so, well, happy," said Jackson, gazing out of her South 17th Street "Happy" display window. "They see the display, they start dancing, and they come in my store."

First Impressions in Lafayette Hill is now selling its second order of the T's. In addition to Peace Love World, owner Pam Katz carries other positive apparel brands such as Lauren Moshi's tanks, tops, and shorts adorned with giddy emoticons; and California-based Junk Food Clothing Co.'s bolder graphics, like the floral muscle T that says "Good Times Day & Night."

Even seasoned California-based designer Michael Stars is getting on the good-vibes bandwagon with power words like "Dream" and "Live."

"It's a form of self-expression, a modern form of spirituality," said Katz, explaining that the edgy skull prints of yesterday are being replaced with love and light themes. "We were in such a period of glitz and glam that's just over."

Happiness - or the search for it - has been a buzzword in pop culture for a few years as people start to tire of mass consumerism and the race to try the latest technology.

Ironically, perhaps, retail options are "a natural evolution of this movement," said Ann Mack, director of trendspotting at JWT, a New York-based market research firm. "As marketers take advantage of the linkages between happy and healthy, it's represented in the product they make."

We may be embracing the happy messages to counter our social-media obsession, Mack said, yet the simple affirmations like "Joy" and "Live on Purpose" happen to have a 140-character quality to them.

That hashtag effect may be new, but inspirational messages aren't when it comes to sportswear. Remember Nike's 1988 "Just Do It" campaign? Over the years, workout words like sweat have been motivational, and peace and breathe have grown with our interest in yoga and meditation.

During the spring 2014 runway collections, Westwood sent tops with "Climate" down the runway, and London designer label Sister by Sibling went with "Happy," said Jaclyn Jones, womenswear editor for New York-based trend company WGSN.

"These emotive words and feelings are becoming a declaration of our personal mantras," said Jones. "They are what we want to tell others about who we are in the simplest way possible."

Clothes and accessories courtesy of:

Coeur, 132 S. 17th St., 215-972-0373,

First Impressions, 470 Germantown Pike, Lafayette Hill, 610-828-6775.