Kate McKinnon is a breakout cast member of “Saturday Night Live” and a featured player in the coming reboot of “Ghostbusters.” Her star certainly seems to be on the rise. When Ford Motor cast her in a new ad campaign for its Focus, however, it did so knowing the commercials would never appear in a place where stars are usually meant to be seen – TV.

Want to take a gander of McKinnon’s Ford-backed portrayals of a daredevil archaeologist or an uptight hedge-fund manager? You have to surf the digisphere. Ads for Ford’s Focus feature McKinnon as an anthropologist trying to determine what kinds of people would best be suited for the car, then portraying each of those potential customer types, whether it be a fashion model or a guitar-wielding glam rocker. The spots, expected to run until the end of this month, last anywhere from 90 seconds to two minutes. And they, or snippets and outtakes from them, are available for view via YouTube, Twitter, Snapchat, Tumblr and Instagram.

It’s a lot of work for a busy actress or comedienne, but that’s what’s needed to make a dent in the nation’s pop-culture membrane in the digital age. “If people are spending less time watching TV and more time on a mobile device, more time online, that’s where we need to reach out and find them,” explained Doug Patterson, senior vice president and group creative director at Team Detroit, the WPP-owned ad agency that worked on the effort for Ford. “We need to tailor communications to work in those mediums.”

The celebrity ad isn’t about to disappear from TV, as the seeming ubiquity of recent pitches from Lincoln sporting Matthew McConaughey and Old Navy featuring Julia Louis Dreyfus can attest. Indeed, MasterCard agency McCann XBC recently created a new commercial featuring – yes – Kate McKinnon. In some cases, however, it is moving away from the medium with which it has long been most associated.

Grace Helbig seems like another entertainer on the rise who would fare well in TV commercials. She is popular on YouTube but also has a series on the E! cable network. Marriott International recently started a promotional effort that stars her but can only be seen on the Google-owned streaming-video outlet and other digital venues. “She had input on the script. She gave us some ideas to make it better, make it more authentic and natural to her tone, voice and style,” said David Beebe, the hotelier’s vice president of global creative and content marketing.

And that seems to be the key reason behind the migration of stars from living-room screen to stuff designed for mobile devices. At a time when anyone can cut loose on Vine, Periscope or Meerkat, a 30-second TV ad remains very buttoned-down: Product attributes must be mentioned before allotted time runs out. The streaming-video efforts, on the other hand, allow the celebrities to add signature touches once some of the hard sell is out of the way. Without the famous figure cutting up and letting loose, the online video pitches would likely have a harder time going viral and getting passed along by consumers.

The various characters seen in the Ford ads were outlined for McKinnon as part of the assignment, said Thomais Zaremba, manager of digital marketing and media for Ford Motor. “The bringing of the characters to life, all of that was improvised and what she brought to the table,” she said. A Ford spokesman said McKinnon was not available for comment. Her antics, said Zaremba, were instrumental in helping Ford attract young, female car buyers and try to start a “conversation” with them that might prompt them to seek out more information about the Focus.

Advertisers using digital video “will have more freedom, fewer restrictions, and they’ll be ‘showing’ in the media where their younger audience is hanging out,” said Edward Boches, a professor of advertising at Boston University and a former advertising executive. “It’s an approach that leaves room for discovery, sharing and commenting – and by using celebrities that have their own followings, they enable the campaign to get a quick out-of-the gate-hit.”

There is some evidence that streaming-video pitches may draw more attention from younger viewers who are prone to using a commercial break on TV to fix their gaze on a smart phone screen. A survey by Deloitte of 2,076 U.S. consumers found people put just as much stock in an endorsement from an so-called “online celebrity” as one from a famous person from more traditional origins. The consultancy also found four out of five millennial viewers felt they were more distracted during TV ads than digital ones.

The digital route represents a useful path for advertisers who want to spend smartly. Running sharable videos online can spark fans to take the commercials and post them on other sites, noted Michael Schiferl, an executive vice president at Weber Shandwick, a public-relations firm owned by Interpublic Group. His agency did some work for Yum Brands on an advocacy project that involved Christina Aguiliera, who was nearing the due date for the birth of a child. Days after the campaign launched, the singer would no longer be available. The agency put together a video featuring Aguilera, who used her social-media outlets to call attention to it, and fans began to spread it around, said Schiferl.

“The ripple from that was enormous,” he said. “From just one digital spot we put out, we were able to extend the reach really quite far.”

Success in this new arena is far from guaranteed. “You can’t, no matter what anyone says, make something go viral,” said Bosches, the advertising professor. “You can do a YouTube buy and jump-start it, but only if the content is freaking great, strikes a fancy, and gets shared organically will it get a lot of eyeballs.” As long as Kate McKinnon is willing to do six different versions of a commercial and play umpteen different roles to make them stand out, advertisers will probably remain willing to experiment.