Game of Thrones has started a new campaign in collaboration with the American Red Cross--and the guidelines associated with it are stirring up some controversy.

The HBO series' campaign, called "Bleed for the Throne," is encouraging fans to donate blood for an exclusive t-shirt and a chance to attend the premiere of season eight. However, per the guidelines set by the FDA, gay men must have abstained from sex for a full year before donating blood, and women who have had sex with bisexual men in the past year are also not eligible for donation. In addition, groups such as people with diabetes and hemophilia are also not eligible to donate. This means that they would not be allowed to donate blood to enter the contest.

The guidelines come out of rules set during the AIDS crisis in 1983, and it wasn't until 2015 that the lifetime ban for gay men to donate blood was lifted.

Fans excluded from the contest are obviously upset, especially given the large-scale presence of the drive at events like SXSW. HBO later announced that fans who are not eligible to donate blood per the FDA guidelines could still enter by contacting the Red Cross Donor Support--information which was not originally included in the promotion.

The campaign and sweepstakes will continue through March 12, and Game of Thrones' season eight premieres about one month later on April 14.