Alexis Ohanian, founder of the submission-based sharing platform, posted a video last week announcing the gift exchange, which allows users to send care packages to other users who are serving in the military overseas.

Issa signed up to participate in the gift exchange, according to his office. He then tweeted about the opportunity.

Colbert was the first user to sign up to send a care package, according to Ohanian in the video. The Comedy Central host of "The Colbert Report" also appears, sporting a Redditgifts T-shirt, on the sign-up page. Sign ups end June 18.

Reddit already hosts “the world’s largest secret Santa gift exchange," according to Ohanian. As of Tuesday, more "givers" than "receivers" (members of the military) had signed up for the exchange.

Issa’s use of Reddit is rare on Capitol Hill, where YouTube, Facebook and Twitter are more widely used. In March, he participated in a live, wide-ranging chat with other Reddit users.