Each week on 'The Glee Project,' a cast member from 'Glee' guest-stars to help the contestants with their challenge for that week. On the June 26 'Vulnerability' episode, Dot-Marie Jones, aka Coach Beiste, stepped in to assist the contenders by teaching them to use their weaknesses to make their performances more real and relatable.

"I know with Coach Beiste, I relate a lot of personal experiences in my life," Jones told the 10 remaining competitors, who seemed starstruck. She revealed that much of the drama surrounding her 'Glee' character comes from a very real place. "I was always big and I hear 'sir' every single day of my life. I've never been a sir, nor do I want to be a sir. The times that you've seen me cry, those were real."

It was Jones' job to choose who gave the best and most vulnerable performance during this week's homework assignment, which was Pink's 'Please Don't Leave Me.' Jones picked Matheus Fernandes, who offered more than just words with his line from the powerful song. He earned a featured spot in this week's music video, Tears for Fears' 'Mad World,' and a one-on-one coaching session with the coach herself.

During his session, the obviously short but big-attitude singer revealed his vulnerability: That he's small. But when he sang, he looked into Dot's eyes and delivered the message that his size doesn't determine his worth.

Dot-Marie Jones is the third 'Glee' famer to appear on the Oxygen show, following Idina Menzel last week and Darren Criss on 'The Glee Project' premiere episode.

See 'The Glee Project' Contestants Meet Dot-Marie Jones