In addition to stellar mash-ups and one-of-a-kind cover renditions, ‘Glee‘ gets its good name for its guest stars. The show will step up in 2012, bringing Helen Mirren to the set … In some capacity.

Apparently, the 66-year-old British actress — who is known for a long list of acting credits — will only be appearing vocally, not physically. Mirren will offer her sweet speak as the inner-voice of one of the ‘Glee’ characters, according to TV Line.

In fact, the ‘Glee’ writers specifically wrote said role with Miss Mirren in mind, so when she agreed to do it, everyone was thrilled, though her appearance was a surprise to the New Directions crew. “Helen came in and secretly recorded several long and hilarious monologues two weeks ago,” a source reports. “Then she visited the kids on set, and they had no idea she was coming; they were stunned.”

The source admits that snagging Mirren was easy, as she’s friends with director Eric Stoltz and thinks that the hit FOX show is making positive waves in the world. “Helen’s a big fan of the show,” the source says, adding, “and the message it sends out about arts education.”

Rumor has it that Helen’s voice will make its debut on the Jan. 17 episode of ‘Glee,’ which is the first episode of 2012.