Former president Donald Trump can't seem to keep his walls straight.

During an interview with Fox News' Sean Hannity on Thursday night, Trump appeared to confuse a completely metaphorical wall with his actual border wall.

Referring to President Joe Biden, Hannity said, “So, you keep banging your head against the wall — why would you expect a different result?”

Trump responded: "So, we would have had the wall completed in three weeks. It was largely completed. We did almost 500 miles of wall.”

Coincidentally, Trump also bragged during the interview about once "acing" a cognitive test.

Video and reactions from Twitter below.

Trump has a senior moment on Fox News — then brags about acing a cognitive test www.youtube.com