Chord Overstreet paid tribute to his fallen friend and 'Glee' costar Cory Monteith yesterday (July 20) with an emotional acoustic performance.

Overstreet closed the acoustic part of his set at Roxy Theater in West Hollywood, Calif. with a song that brought fellow costars Jenna Ushkowitz and Dianna Agron, who were on hand in the VIP section to support, to tears. Other stars in the VIP crowd included 'Glee' star Kevin McHale and 'Dancing With the Stars' and 'Rock of Ages' starlet Julianne Hough.

"I wasn't going to play this but ... I recently have been going through a lot of stuff with a losing really, really dear friend of mine, so I want to play this song for him," Overstreet stammered. "This is for you, Cory. I sang this with Kevin McHale and Cory Monteith. I love you buddy."

Overstreet then launched into 'Billionaire.'

After the show, Just Jared reports that Overstreet and his costars hugged backstage and even voted McHale as VIP fan of the day for encouraging the crowd to sing along to Overstreet's songs. While the cast may not have Monteith with them anymore, they still have each other.