Lady Gaga got in character by throwing a blood-red pool party for the American Horror Story: Hotel cast over the weekend.

The 29-year-old singer will star on season 5 of the FX horror drama, and teased photos from the fête on Instagram. "A bloody pool for the cast, sorry #AHSfans, there's few pictures. At my parties, killer friends have more fun, when no evidence is left behind," she wrote.

Series creator Ryan Murphy also alluded to the bloody bash, tweeting, "Last night I had a dream that the Hotel cast went to Gaga's house and at midnight swam in her pool that she dyed blood red just for us... Wait a minute, that was no dream... THAT ACTUALLY HAPPENED."

The party fueled rumors Lady Gaga will play an Elizabeth of Bathory-like character on the show. The real-life Hungarian countess was accused of killing hundreds of young women between 1585 and 1610, and is said to have bathed in blood in an attempt to retain her youth.

The singer had changed her Instagram username to "The Countess" as interest in the upcoming season gained momentum. Murphy previously revealed the star will play an "evil" hotel owner with a "nefarious" plan that plays out throughout the season.