Nothing can get Katharine McPhee down.
"Dear @katharinemcphee don't EVER sing ‘to love you more'," said the Twitter user. "The fact that @officialdfoster would let you butcher that song – a classic at that, WOW!"
"To Love You More" was written by McPhee's husband, David Foster in the early 1990s and won a handful of awards after its 1995 release.
McPhee, however, didn't feel bad about flubbing a few notes while performing the song for a 2018 PBS special.
"I'd like to see you try this, b---h," wrote McPhee on Twitter, attaching a video of her performance.
When asked how the "Scorpion" star would assist with the nuptials, Erin, 37, said that she hoped McPhee would perform at the ceremony.
"So Kat wrote me the other day, she was like, 'Is there anything that I can be doing to help you prepare?'" Erin told E! News. "And I said, 'Yes. Vocal exercises. Prepare your voice because you will be performing.' She's like, 'OK.'"
Erin's sister Sara, however, later said that McPhee's wedding performance was up in the air.
"Well, they haven't said 'yes' [to performing]," said Sara of their dad, 70, and McPhee. "She might have to pay them to do that. They charge a lot of money to do things like that. So she is just assuming that they'll do it, but she hasn't asked formally."
Erin was hoping that the singer would perform a song from the Broadway musical "Waitress."