"Glee" fans rejoice. This week's "Glee" episode will feature two well-known power belters again, the American idol standout Adam Lambert and "Frozen's" "Let It Go" singer, Demi Lovato. The two singers are returning to Fox's Hit musical series "Glee" this week for their extended guest starring character arcs. For those who cannot wait until this week's episode to air, a first look at the actors in action with "Glee" lead Chris Colfer is now available to view. Way to go and increase your excitement.

Below is also the trio's take on the Happening:

The synopsis of this week's episode entitled "Trio" is as follows: "As graduation approaches, Tina, Blaine and Sam band together to hold a senior "lock-in" at school, hoping to savor their last chance at hanging out together. But their plans are thwarted when Becky joins unexpectedly. Meanwhile, in New York, Elliot (guest star Adam Lambert) is stuck in The Middle between Rachel and Santana's feud." Adam Lambert's fans can enjoy because for sure this episode will bring out their idol's acting skills, and of course, singing and rocking prowess.

Demi Lovato on the other hand has been very busy with her "Neon Lights" tour has still managed to shoot for "Glee." On her days off from her Tour, Demi Lovato can be seen on various events too. It's a mystery how she can be so busy and yet still manage not to strain her megawatt singing prowess.

Demi Lovato even got time for a selfie with the president Bill Clinton. Too excited to keep the photo for herself, she immediately took to Twitter and posted the picture. If she is not going to awards, meeting with presidents, and staging concerts, Demi Lovato is also hanging out with best friend Selena Gomez. In fact, the two girls were at Thursday's unite4:Humanity gala event bonding.

The girl obviously has loads of energy. Fans should watch this week's episode of "Glee" to catch more of Demi Lovato.

"Glee" airs on Tuesdays at 8 PM on FOX. Moreover, the highly anticipated 100th episode airs on March 18.