. . "Dierks Bentley and Josh Groban have also signed on to perform on Teachers Rock, which honor educators from across the US who have contributed to their communities.Teachers Rock will feature taped vignettes where stars including Usher, Meryl Streep, Dave Grohl, Adam Levine and Jennifer Garner sharing memories of their favorite teachers.Maggie Gyllenhaal and Viola Davis - who appear in the new educa" . .