In anticipation of the return of Glee following a month-long hiatus, excited fans expressed their delight on Twitter, causing the hashtag #gleeisback to trend worldwide on Tuesday morning. The new episode, titled Big Brother, airs tonight at 8 pm on Fox.

Big Brother will be the 15th episode of Glee's third season. The episode will include the introduction of Matt Bomer as the older brother of Blain Anderson (played by Darren Criss). Boomer, in the role of Cooper Anderson, returns to Lima to visit his brother. Meanwhile, the members of glee club take part in senior ditch day and visit an amusement park.

The episode focuses on Quinn's character, who will sing two songs, while Matt Boomer sings Gotye's haunting Somebody That I Used to Know. Bomer and Criss will also sing a duet mashup of Duran Druan's Hungry Like the Wolf and Rio, at the start of the episode, and Criss sings Fighter by Christina Aguilera. All songs performed during Big Brother will be available for sale on iTunes.

The new episode will welcome back the starring cast, as well as recurring guest stars Sam Evans (Chord Overstreet), Rory Flanagan (Damian McGinty), Sugar Moss (Vanessa Lengies), cheerleader Becky Jackson (Lauren Potter) and recent transfer student Joe Hart (Samuel Larsen).

Best Tweets From Twitter Trend #gleeisback:

@msleamichele: So excited though that a new episode of Glee is on tonight! The episode is called Big Brother and it's really good! #gleeisback

@FansOfMonchele: #Gleeisback people! Longest 7 weeks of my life! Happy #Glee Day :D

@joordsss14 : Happy Glee day! #Gleeisback #Gleek

@BrielleFed: I know I'll get mocked for this but I don't care, I'm so excited! #gleeisback

@jess_maynerich: Finally!! I will have some sanity put back in my life. Can't wait!! #gleeisback

@Maya_Melcombe: #gleeisback tonight omg i'm crying

@evildonkey: #gleeisback This does indeed fill me will glee :D

@youvebeenmoz3d: this is how excited I am now that #gleeisback http://www.youtube.com/watch?v=XrObV84tD8g&feature=youtube_gdata_player #INeedAMinute

@Titafarasati: Happy glee day!!! Miss ya a lot new direction! #gleeisback