Guinness today released a new ad featuring the heartwarming story of an athlete who gave up her spot in the Olympics to her sister. But viewers will have to watch the ad quickly before it disappears on Thursday morning.

The spot features biathlete Tracy Barnes, who recently ceded her place on the U.S. Olympic Team to her twin sister, Lanny, after Lanny was too ill to compete in some of the qualifying races.

But the ad must be pulled soon to comply with U.S. Olympic Committee rules that generally prohibit marketers who are not official sponsors from featuring Olympic competitors, according to Guinness. This year's ad blackout runs from Jan. 30 to Feb. 26, according to rules posted on TeamUSA.org.

Technically, all competitors appearing in ads must get permission from the IOC executive board. But waivers for USOC sponsors "will nearly always be granted," while permission "will not be granted to companies that compete with USOC sponsors," according to the rules.

Diageo-owned Guinness is not an Olympic sponsor but competing brand Budweiser is an official Team USA sponsor. So Guinness wanted to take advantage of the short window it had by making a one-day media buy, including TV, YouTube and print ads in daily newspapers.

"We are not doing this as a guerilla marketing tactic to ride the wave of the Olympics," said Diageo spokesman Jim Sias. "This is just a really powerful, inspirational story that we think really aligns with the DNA of what the Guinness brand is," he added. "We really wanted to celebrate it and make this story more known and recognize it."

The ad, by BBDO, New York, is part of the brand's "Made of More" campaign. It was put together quickly in the wake of the Olympic team trials earlier this month. As NBC Sports reported, "Lanny was just out of the running until Tracy informed her of a decision she made before that final race."

"Love means giving up your dream so someone else can realize theirs," Tracy Barnes said, according to 3 Wire Sports.