The commercial breaks during Sunday's big game were unusually glitzy. This year’s slate of Super Bowl ads contained an unusually high concentration of star power: star turns from Liam Neeson (Clash of Clans), Lindsay Lohan (esurance), Jeff Bridges (Squarespace) and Kim Kardashian (T-Mobile); ads narrated by Common (Microsoft) and Aaron Paul (Weight Watchers); surprise appearances from Bryan Cranston (esurance) and Steve Buscemi (Snickers); even a few speeches from Muhammad Ali (Toyota) and JFK (Carnival Cruises) were repurposed.

“I think the celebrity angle helps,” said Peter Daboll, CEO of Ace Metrix, which evaluates the effectiveness of digital video advertisements. “But only to a point.

“It gets that initial attention,” he continued, “but if you don’t do something with it, you’re in trouble.”

A celebrity’s presence doesn’t guarantee an ad any lift. Indeed, early returns suggest this year's investment in stars didn't deliver. According to research conducted by Ace Metrix, the night’s highest-rated ad was McDonald’s “Pay With Lovin',” a celeb-free spot highlighting the fact that random McDonald’s customers will be able to pay for their meals with acts of kindness or compassion rather than money for the next few weeks. Most of the other top-rated ads, including Budweiser's "Lost Dog" and Always' "Like a Girl," featured no celebrity presence.

“We saw a handful of brands really going for this positivity kind of thing,” said Daboll, who cited brands like Coca Cola and Always for airing ads that aimed for uplift rather than laughs or surprises. “This was the right balance of fun and positivity without being lecturing.”

So why all the celebrity skin this year? The desire to minimize risk probably played a role. With Super Bowl airtime priced at a record $4.5 million per 30 seconds, advertisers may have wanted to do as much as possible to make sure their ads were well-received by viewers.

“When you spend [so much] just for media it is understandable to play it safe,” Adam Broitman, Mastercard’s vice president of global digital marketing, tweeted. “Wholly uncreative, but understandable.”

Indeed, most of the celeb-heavy ads were promoted ahead of time, either through teaser content or an outright leak of the full ad before Sunday’s broadcast. Only Liam Neeson and Bryan Cranston were surprises.

“Time is ticking like a bomb on these ads,” Daboll said. “It’s so expensive. If you can’t establish your story quickly, you run the risk of people drifting off. Using a celebrity helps people connect more quickly.”

It certainly helps with promotion. Kardashian, for example, who has more than 28 million followers on Twitter, has been tweeting about her Super Bowl star turn with T-Mobile for almost a week. And it is highly unlikely digital sports outlets like USA Today's FTW blog would bother to have linked to Wix's ad if it hadn't involved Brett Favre and Terrell Owens.

The stars themselves are attracted to a quick check and a nice boost to their own profiles. A well-received Super Bowl commercial, like the 2010 Snickers ad starring Betty White, can thrust a star back into the spotlight virtually overnight. Even an ad that does less well, like Sunday's mysterious Squarespace ad starring Jeff Bridges, will normally reflect poorly on the brand rather than the star.

"I hope he got paid a lot," Daboll laughed when asked about Bridges. "That was the weirdest ad."