After months of anticipation, the crossover between The CW's four DC Comics-based superhero shows -- "Supergirl," "The Flash," "Arrow" and "DC's Legends of Tomorrow" unfolds this week through Thursday.

The CW has produced t-shirts commemorating this week's "Invasion!" crossover, based on the comic book storyline of the same name, and the bad news is, they're quite rare -- only 65 were made. The good news? CBR has five of them to give away! Read on for more information on how to enter.

GIVEAWAY DETAILS AND PRIZES

Five winners will each receive one "Heroes vs. Aliens" t-shirt, featuring Supergirl, Green Arrow, The Flash and White Canary, Firestorm and The Atom of "Legends of Tomorrow;" with a building strongly resembling the Hall of Justice from "Super Friends" in the foreground.

heroes-vs-aliens-tshirtfront
heroes-vs-aliens-tshirt-back

HOW TO ENTER

You can enter multiple ways, and each person you refer will earn you extra entries. To enter -- from 3 p.m. ET Tuesday, Nov. 29 to 5 p.m. ET on Friday, Dec. 2 -- use the widget below: (Must be over 18 to enter)

a Rafflecopter giveaway

Eligibility: Open to legal residents of the United States who are 18 years or older. Void where prohibited or restricted by law. Sponsor, prize supplier and their respective parents, subsidiaries, affiliates, distributors, retailers, sales representatives, advertising and promotion agencies and each of their respective officers, directors and employees (collectively, the “Promotion Entities”), and members of their immediate families and/or persons living in the same household as such persons, are ineligible to enter the Sweepstakes or win a prize.

"Invasion!" starts in earnest at 8 tonight on The CW with "The Flash," continues Wednesday with "Arrow" and concludes Thursday with "DC's Legends of Tomorrow."