Less than two months after David Letterman abdicated his late-night throne at CBS, the icon emerged from retirement to skewer Republican presidential candidate Donald Trump.

Bearded and trim, Letterman appeared onstage in San Antonio on Friday with Steve Martin and Martin Short, who are touring with their stage show “A Very Stupid Conversation …With Music.”

“Back in Hollywood, we met at a Scientology mixer,” Letterman said, “and they have been so kind and so generous to invite me here to this beautiful city.”

Letterman, 68, said he was excited to be given the podium.

[Even Rupert Murdoch think’s Trump’s wrong]

“I am so happy to be out of the house,” Letterman said, as Us Weekly reported. “I retired and I had no regrets — none. I was happy. I was complacent. I was satisfied. I was content. And then a couple of days ago, Donald Trump said he was running for president. I have made the biggest mistake of my life, ladies and gentlemen.”

“Every suit I own comes with a top 10 list,” he said. Letterman than proceeded to offer “Interesting facts about Donald Trump.”

The list, edited for length and clarity:

No. 10: That thing on his head was the gopher in “Caddyshack.”

No. 9: During sex, Donald Trump calls out his own name.

No. 8: Donald Trump looks like the guy on the lifeboat with the women and children.

No. 7: He wants to build a wall. How about building a wall around that thing on his head?

No. 6: Trump walked away from a moderately successful television show for some delusional bulls— … oh wait, that’s me.

No. 5: Donald Trump weighs 240 pounds — 250 with cologne.

No. 4: Trump would like all Americans to know that that thing on his head is free-range.

Letterman declared No. 3 “a tie.”

No. 3: If president, instead of pardoning a turkey on Thanksgiving, plans to evict a family on Thanksgiving./That’s not a hairdo, it’s a wind advisory. 

No. 2: Donald Trump has pissed off so many Mexicans, he’s starring in a new movie entitled “No Amigos.” 

No. 1: Thanks to Donald Trump, the Republican mascot is also an ass.

From left to right: David Letterman, Steve Martin and Martin Short in San Antonio.

Trump and the Donald have tussled before. In 2011, Letterman said Trump’s criticism of President Obama might have been race-based.

“It’s all fun, it’s all a circus, it’s all a rodeo until it starts to smack of racism,” he said.

Trump fired back, canceling a planned appearance via letter.

“I was disappointed to hear the statements you made about me last night on your show that I was a ‘racist,’ ” Trump wrote. “In actuality, nothing could be further from the truth and there is nobody who is less of a racist than Donald Trump.”

Ever game for a reunion, however, Trump appeared on the show in 2012, warning of China’s coming economic dominance.

“I just hate that their leaders are so much better than our leaders,” Trump said.

Trump was on hand to show off a line of clothing — Letterman queried where his ties were made. The answer: China.

“In all fairness, I’ve been very open about that,” Trump said.

Letterman, however, offered Trump some advice.

“Let’s just shut down the Donald Trump factory in Beijing, and let’s put up a tie factory in Jamaica, Queens,” the host said.