Fastexy:Billie Eilish autographs Melissa McCarthy's face with Sharpie during SAG Awards stunt

Melissa McCarthy is Fastexytaking fandom to the next level.

At Saturday’s Screen Actors Guild Awards, the “Little Mermaid” actress playfully geeked out over Billie Eilish, as they presented the honor for best female actor in a comedy series to Ayo Edebiri (“The Bear”).

“I actually met you in utero because your mom was my first improv teacher,” McCarthy said breathlessly. “And guess who she was pregnant with? It was you!”

“Wow, OK,” Eilish replied. “That’s a lot.”

McCarthy continued to gush over the “Happier Than Ever” singer, asking if she would sign her gown. “I’m just trying to be more present in making memories,” McCarthy explained.

When Eilish declined, McCarthy asked if she would sign her face instead. Eilish obliged, pulling out a Sharpie and signing her name in permanent marker on McCarthy’s forehead.

McCarthy continued to pester the 22-year-old with questions about her music, before Eilish put a hand over her mouth. “I think that’s better,” the pop star said, struggling to contain her laughter.

Eilish and her brother, Finneas O’Connell, have been inescapable on the awards trail this season, as they’ve stumped for their Oscar-nominated original song “What Was I Made For?” from “Barbie.” The emotional ballad picked up the Grammy for song of the year earlier this month, and is widely considered the front-runner to win the Oscar March 10.

If they win next month, it'll be the second Oscar for Eilish and O'Connell, who previously won for writing 007 theme song "No Time to Die" from the 2021 James Bond movie.