Anna's raunchy on-screen moment made headlines as BBC presenter Sophie Raworth, 49, appeared completely oblivious to the steamy action being shown behind her as she read the headlines of the night, with many people at home mistakenly thinking that porn was being accidentally shown to millions of viewers.
"It's objectively amusing!" she tweeted.
The nip slip-up happened because an episode was playing on an employee's computer in the background of the live broadcast. "Thanks for the giggle!"
The back left monitor in the 12-second clip above shows a sex scene from "True Blood", during which Paquin takes off her top as well as her bra.
Stephen, Anna's husband, said the BBC blunder was making him "very happy".
Anna also joked about the BBC's reaction to what was seen on TV, questioning a statement which said they were "looking into the matter".
Anna describes the scene shown as "fairy land graveyard sex", where her character, Sookie Stackhouse, gets intimate with Robert Kazinsky's half fairy, half vampire character. "What's there to look into my t**s photobombed the news because someone was watching #trueblood in view of camera", Paquin responded, to which a fan pointed out that the 35-year-old could now use the phrase "photoboobed".