‘Supernatural’ Stars Tease “Cathartic, Emotional” Winchester Family Reunion in 300th Episode

The Winchester family will be made whole in Supernatural's 300th episode, reuniting sons Sam (Jared Padalecki) and Dean (Jensen Ackles) and parents Mary (Samantha Smith) and John (Jeffrey Dean Morgan).

"My first thought on episode 300 was that the fans were gonna lose their minds. Because it's a reunion that we're seeing in this episode that I think we've all been pining for for the last 12 years," Misha Collins, who plays ally angel Castiel, tells EW in the above video.

"I think everyone has been waiting for John Winchester to come back, so it was a real coup to get him back. And we're all psyched about that."

For Jeffrey Dean Morgan, who has since gone on to land a starring role as bat-swinging bad guy Negan in The Walking Dead, the actor has long been hopeful to return as the late hunter of all things supernatural whose work is now carried on by his two sons.

"We've been talking years, since I left the show, on a way to come back and when was gonna be the right time," says Morgan, who last appeared in a 2007 episode of Supernatural's sophomore season. "It was a thrill. I was so happy to be there that I didn't want to leave once I got there."

A new encounter with the long-dead John — brought about in the form of wish fulfillment by an aching Dean — will allow the father and sons their chance at closure.

"For me it was really almost cathartic experience to film with Jeffrey," Padalecki says. "All in all I felt like it really served the story well to have Sam and John have a chance to kind of hash things out."

Adds Ackles, "I know I really enjoyed the scenes that were written between the father and the sons, not to mention just the image of seeing mom and dad together."

The reunion proved emotional for Smith, whose Mary was killed long ago by the Yellow Eyed Demon. Her death would later be avenged by John, who later struck a deal trading his life for Dean's before Mary's own eventual resurrection.

"So when I read the script for the first time, I literally cried the whole way through," she says with a laugh. "To get to say the things that weren't said and to have that chance that nobody ever gets when somebody's gone is so huge, it's hard to even articulate."

All of Morgan's scenes in episode 300 have "a lot of weight" to them, Morgan teases. "And it's gonna be emotional, and it'll be funny at times, but I think that it's gonna really tug on some heartstrings."

"There's also really good moments of John seeing his sons as men, which he never has," Ackles adds. "And hearing about these accomplishments that these boys have gone through."

It's those familial bonds, both on screen and off, that ensured the longevity of the fan-favorite CW series, Smith explains.

"Many shows say, 'Oh, it's a family, it feels like family, and everyone loves each other.' The difference about this show is that I think it really takes it to a next level, and there are multiple families within the family," she says.

"So there's the fandom family, and the cast family, and the cast and crew family, and it is what has propelled it to this point."

"I think what makes Supernatural is so special is the fandom. And when you have that kind of relationship and honesty with your fans, and you give a piece of yourself to these people, it makes something very special," Morgan says. "I mean, to do 300 episodes, it means that you have people that love you."

Supernatural's 300th episode, 'Lebanon,' premieres on The CW Thursday, February 7.