The 'Glee' star made his first red carpet appearance alongside his co-star and girlfriend at the 12th annual Chrysalis Butterfly Ball in Los Angeles on Saturday night (08.06.13) since completing a month of treatment for addiction in April.
Looking dapper in a grey Calvin Klein suit, white shirt with small polka dots and a matching tie, the 31-year-old actor said he was thrilled to lend his support to the cause, which helps homeless people and low-income earners gain employment.
He told EOnline.com: ''I'm happy I could be here to support an amazing organisation. Chrysalis is empowerment. It's not just a handout. It's empowerment. It's taking people who just need a help up.''
Lea, 26, was delighted to be by her boyfriend's side and said: ''I think he looks great, doesn't he? He's the best.''
The couple first revealed they were dating at the charity bash last year.
Other guests at the event, which was held at a private residence in Brentwood and raised $1.25 million for the charity, included Colin Farrell, Rebecca Gayheart-Dane, Eric Dane and director David O'Russell.
Cory has been keeping a low profile since checking into rehab at the end of March.
The actor - who had been clean since going to rehab at the age of 19 - voluntarily checked in for treatment again after he was reportedly led astray and started drinking and taking drugs at parties at his Hollywood Hills home.
A spokesperson for the actor said at the time: ''Cory Monteith has voluntarily admitted himself into a treatment facility for substance addiction. He graciously asks for your respect and privacy as he takes the necessary steps towards recovery.''
He and Lea have enjoyed several vacations together following his release and were most recently spotted soaking up the sun in Puerto Vallarta, Mexico last month.