Stephen Colbert had just two letters for Sen. Ted Cruz after the Texas Republican launched a bizarre attack on Big Bird.

Last week, after the “Sesame Street” character tweeted that he had been vaccinated, Cruz replied: “government propaganda... for your 5 year old!”

Colbert fired back in a style true to the street. “Sesame Street,” that is.

“Senator Cruz, how should I put this?” Colbert said. “Our show tonight is brought to you by the letters ‘F’ and ‘U.’”

“I’m surprised Cruz is at odds with Big Bird here,” Colbert added. “They have so much in common: When it gets cold, they both fly south.”