Cooper, People magazine’s 2011 “Sexiest Man Alive,” sat down with Biden at the White House earlier this year.

He also spoke at a January press conference on mental health at the Center for American Progress in downtown Washington with former Rep. Patrick Kennedy (D-R.I.) and Sen. Debbie StabenowDebbie StabenowFight over water bill heats up in Senate Overnight Energy: Senate Dems set to fight water bill Senate Dems may block water bill over drought language MORE (D-Mich.).

UPDATE (2:30 p.m.): Cooper told a crowd at the conference Monday afternoon, "I think that all of us are touched in a real meaningful way with this illness. And I think it is up to all of us to help. I want to help, I want to do something about it. I want to be part of the solution," before introducing Biden.

The vice president quipped, "I'm Joe BidenJoe BidenClinton reappears on Capitol Hill for Reid send-off The Hill's 12:30 Report The Hill's 12:30 Report MORE, and I'm a friend of Bradley Cooper."

During his closing remarks, Biden told a story about staying at the same hotel as the "Hangover" star during a recent trip to Brazil. Joking that the entertainer had "caused me a great deal of pain recently," Biden said he had to disappoint his 12-year-old granddaughter by meeting with the president of Brazil rather than summoning Cooper to his suite.

"My standing with my granddaughter has plummeted," Biden cracked.

Justin Sink contributed.