Just in case you’re tempted to spend your entire advertising budget on hiring the biggest star names possible for your campaign – Timberlake, Tatum, Titchmarsh – think again. It’s probably a waste of money.

According to Unruly’s latest study, celebrities alone do not drive online ad sharing. 

Went it comes to major televised events, such as the Super Bowl where advertising space is hotly contested, the indication of success is no longer viewing figures. It’s online shares.

Shares prove that a viewer has responded positively with an advert rather than passively catching it in the corner of their eye as they reach for more nacho cheese.

This year in particular saw very few viewers citing celebrities as a key driver of why they would share an ad, despite celebrities being out in force during Super Bowl 2014.

Arnold Schwarzenegger, U2, Ellen DeGeneres, The Muppets, even Bob Dylan, all made an appearance this year. However despite this star power, online shares of adverts that aired during the 2014 Super Bowl decreased by almost a third from the previous year. This is the first time that shares of Super Bowl ads have decreased year-on-year.

As much as I’d like to entirely blame the influence of U2, it seems there are even bigger reasons for this downturn that dwarf even Bono’s self-importance.

None of the top three most shared ads from Super Bowl 2014 featured celebrities. Trotting out a barely literate, elderly action hero does not an engaging advert make.

It used to work, perhaps in simpler times when we were less immune to the power of a Hollywood star. Celebrities with large fan followings have successfully endorsed products for years and consumer action has followed accordingly. However, the data suggests the presence of celebrities in a video doesn’t correlate with online sharing. 

Only three of the top 12 Super Bowl ads and one of the top five Super Bowl ads include celebrities. Meanwhile, other big campaigns starring Ellen Degeneres (Beats – #36), U2 (Bank of America – #20), Bob Dylan (Chrysler – #15), David Beckham (H&M – #22) and Stephen Colbert (Wonderful Pistachios – #33) failed to make it into the top 12.

Here’s another fairly damning indictment: 93% of people who watched Bob Dylan’s Super Bowl ad didn’t even realise it was for Chrysler. 12% of viewers thought it was an advert promoting the campaign to revitalise Detroit, 3% thought it was to promote America while some 4% thought it was a spot for rival Ford. 

Celebrities do not make an ad more intrinsically shareable, they also can detract from the message in the advert or even the brand name itself. 

This trend is not just restricted to the Super Bowl. Despite brands using celebrities for many of their ads, only 13% of the top 100 shared ads of all time feature star names.

Celebrities cannot be relied on to save a low-intensity, mildly shareable ad. Instead concentrate on the quality of the content itself. The top three ads in the chart above all tell a story or convey a simple message. Others use humour or innovation to drive engagement.

Unruly recommends skipping the star power and instead investing in content evaluation and video distribution. If a brand creates an extremely shareable piece of content, pre-testing will predict the levels of earned media they can expect. However, if the spot is intrinsically shareable, the right celebrity presence can certainly amplify shareability.

Check out the full report here: The Science of Sharing.