'Supernatural' star Misha Collins is set to guest star in an upcoming episode of the CW's 'Ringer,' reports TVGuide.com.

Collins will star as Dylan, someone from Bridget and Siobhan's (Sarah Michelle Gellar) past when they were in Tahoe. Dylan plays a pivotal role in the sisters' lives. As it turns out, he's part of a reason the sisters had a falling out.

Collins, known for playing Castiel on the CW's 'Supernatural,' will first appear alongside Gellar in episode 14, which means that we'll have to wait until after 'Ringer' returns from its midseason break to catch Collins in action.

UPDATE: The CW has gone pickup crazy. Not only has Sarah Michelle Gellar's new show, 'Ringer,' received a full-season pickup, the network has also ordered a full 22 episodes of fellow freshman dramas 'The Secret Circle' and 'Hart of Dixie.'

Gellar's anticipated return to TV brought in 2.7 million viewers, and 1.2 million in the 18-49 demographic, for its premiere -- a pretty good start according to the CW's standards. However, the dramatic thriller has been losing steam ever since.

During weeks two and three, the show scored a 0.9 in the 18-49 demographic. Then, the Oct. 4 episode's ratings dropped by 33 percent, to just a 0.6 in the 18-49 demographic. It rebounded on Oct. 11 to a 0.8 rating and 1.7 million viewers.

['Ringer' S01/E01 -- 'Pilot']

'The Lying Game' may have done the twin switch thing on television a few weeks ago for ABC Family, but it couldn't come close to matching the slick production and dense plot layering we saw with the series premiere of 'Ringer' (Tue., 9PM ET on The CW).

Sarah Michelle Gellar made her much-anticipated return to television with a role so big, she had to get two parts. And while sisters Siobhan and Bridget only shared a couple of scenes together, Gellar proved rather adept at carrying on an emotional conversation with herself, such as it is.

Facts must be faced: 'Ringer,' Sarah Michelle Gellar's new identity-switcheroo drama, is a little bit silly.

'Ringer' (9PM ET Tuesday, the CW) isn't terrible. But it's less than it could be, and it has yet to present viewers with compelling reasons for putting up with its contrivances.

Props to 'Ringer' for even attempting a film noir atmosphere on a CW budget, but when a noir doesn't have a sense of visual flair or the right tone of wounded melancholy -- yet takes itself seriously -- it can quickly start to feel mildly cheesy, if not ponderous.

In 'Ringer,' Gellar plays identical twins, and if you value your health, you won't do a shot every time one of her characters is shown in a mirror. (Get it? Two sisters! Identical twins! Mirror images! Get it?)