Julia Louis-Dreyfus: "@lenadunham and I led you to Sean Penn. Your welcome."
Dunham responded: "@officialjld Why won't anyone acknowledge our essential place in fighting crime and allow us to work as a government-sanctioned team?"
The Veep star quipped back: "@lenadunham because they r threatened by our fierce power & undaunted bravery."
Kirstie Alley: "I don't quite get how these "secret" meetings w El Chapo weren't aiding and abetting Americas most wanted drug lord. #RollingStoneSeanPenn ...Forget the "hip" factor. Interviewing El Chapo would be like interviewing Hitler after the war. Both death mongers to millions. #WANTED."
Andy Cohen: "We had hoped to find a way to bring El Chapo into the next #RHOBH Reunion but Mr. Penn once again has screwed up a Housewives Reunion."
Billy Eichner: "When you date Charlize Theron, your only rebound can be El Chapo."
Geraldo Rivera: "Folks getting mad at Penn cause he got chummy w El Chapo Why? Penn wasn't acting as a journalist he was one risking a lot to get huge exclusive."
Kathy Griffin: "You're not gonna BELIEVE what #SeanPenn just told me;) #ElChapo #KATHY."
Tom Bergeron: "Reading about Sean Penn's interview with El Chapo. Almost as dangerous as my interview with Elle Chapstick."
Charlamagne Tha God: "Sean Penn will win at all social functions with that El Chapo story, nobody can top that one. Maybe Jay Z discussing losing 92 bricks. Maybe."
Meghan McCain: "What the hell exactly is wrong with Sean Penn?!?"
Lupe Fiasco: "Somebody start that Sean Penn clock."
Chris Rock: "El Chapo going to fashion jail for wearing Adidas sweats pants and New Balance sneakers. He's an animal."
Greta Van Susteren: "An actor can find El Chapo but not Mexican and US authorities...go figure."
George Lopez: "I don't want to seem selfish , but with the capture of #ElChapo , there goes my PLUS one to The Golden Globes."
Trevor Donovan: "I advised Sean Penn to passionately say "Órale Vato Loco!" upon meeting #ElChapo ...ya know, to break the ice :-)"
Guzman was arrested six months after he escaped from prison for a second time. The arrest was made after a shootout that left five people dead.
ABC News reports that Penn and Mexican actress Kate del Castillo, who reportedly helped set up the meeting, are under investigation. ET reached out to Penn's rep about the interview, but he has no comment at this time.