So sly! Will Arnett pulled one hilarious April Fools' Day prank on Jimmy Kimmel this week.

The Jimmy Kimmel Live! host, 47, detailed Arnett's trick on his talk show on Thursday, April 2, explaining just how much the prank ruined his day.

"I wasted so much time today, it's amazing I was able to even get dressed for the show," Kimmel began. "I got a text this morning from Will Arnett... This is from Will, it says, 'Dude... It's Arnett. As a parent you'll appreciate this...'"

"This is where I should've known something was up," Kimmel continued, going on to read the rest of Arnett's text. "'You see the camera button next to where you type when you text? Hold it down and slide your finger up to the other camera button that's going to come up and hold it, then release. It's all these filters nobody knows about.'" 

Kimmel quickly followed Arnett's instructions, but was not in for new filters upon completion. 

"So I do this because it's something that nobody knows about," Kimmel dished. "Of course I have to get in on it even though I never use filters ever anyway... As soon as I hold the camera button down and I slide my finger up, my phone takes a picture of me and instantly texts it to him." 

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Kimmel then pulled up the less-than-flattering selfie that was sent to Arnett, 44, and explained how the prank took over his life for a few short hours. 

"Now, whatever plans for the day are off — I will now spend the next six hours doing this to all of my friends," Kimmel spilled. See the selfies the funnyman received from his parents, son, coworkers, and friends, including Carson Daly and a mostly naked Anthony Anderson, in the video above!