Super Bowl Sunday is here -- and, as always, there's a vast roster of advertisers ready to vie for fans' attention during game breaks.

Airing a Super Bowl commercial is no easy feat. On top of the reported $11 million price tag for a 30-second spot during the game, brands enlist the biggest actors, invest in dazzling special effects and try to put together an ad that more than 100 million expected viewers will like -- or at least remember.

"It's hard to get this attention -- and there isn't really one recipe," said Linli Xu, an associate professor of marketing at the University of Minnesota. "It has to fit with (each) brand."

That means advertisers get creative and tackle different approaches. Some familiar favourites, like Budweiser's Clydesdales, tap into nostalgia year after year. Others attempt to make viewers laugh with light humour and endless celebrity cameos. And a few take more serious or emotive tones that pull on heartstrings.

Many advertisers have already released their spots ahead of Sunday's San Francisco 49ers-Kansas City Chiefs face off.

Some of these commercials include Christopher Walken dealing with people impersonating him all day for BMW, rapper Ice Spice sipping on Starry after a "breakup" with another lemon-lime soda and ETrade's spokesbabies returning in an ad that shows them playing pickleball -- or "basically tennis for babies."

There's also a slew of mini TV show reunions in ads this year. Jennifer Aniston seemingly forgets she ever worked with her "Friends" co-star David Schwimmer in an ad for Uber Eats, for example. And in a commercial stuffed with celebrity cameos -- including "Judge Judy" Judy Sheindlin -- e.l.f. cosmetics reunites "Suits" stars Gina Torres, Rick Hoffman and Sarah Rafferty in a courtroom spoof.

Of course, not all advertisers release their ads ahead of the game, so there will be surprises on game day. In a US presidential election year, it's possible we might see a candidate ad. And while there have been no indications of such, many wonder if advertisers will capitalise on Taylor Swift's buzz in some way.