Neil Patrick Harris Tweets "Eric Braeden is a D-Bag"

Let this be a lesson. If you insult Neil Patrick Harris' "mother" you're going to be called "D-Bag."

OK! NEWS: NEIL PATRICK HARRIS WELCOMES TWINS!

Young and the Restless star Eric Braeden decided at the last minute to not make a guest appearance on How I Met Your Mother and Neil took to his Twitter to express his anger, Fox News reports.

"Eric Braeden is a D-Bag," Neil Tweeted on Friday. "The actor, (Robin's dad) agreed to a cameo, then last night bailed, saying the part wasn't 'substantial' enough."

Now, Eric has been replaced by Ray Wise.

"Wise is a fantastic actor who makes any part 'substantial,' Neil Tweeted later. "Super excited to welcome him to the family!"

OK! GALLERY: SOON-TO-BE DADS NEIL & DAVID GET INTO SHAPE

But Neil must have figured out that his "D-Bag" comment was going to go over so well and later (somewhat) apologized.

"Now I feel bad for the D-bag comment," Neil Tweeted. "Don't know the guy personally. I'm just fiercely protective of our show."