Chad Michael Murray admits that he wasn't exactly planning to return to One Tree Hill for the final season. 

"I've been busy with different discoveries in my own life ... [and] it never really dawned on me," Murray told TVGuide.com on the show's North Carolina set. "Then the opportunity came, and I knew how important it was to these fans who are everything to the show — and that was it."

The cast of One Tree Hill shares their all-time favorite episodes

On Wednesday's episode, Lucas returns to Tree Hill to comfort his best friend Haley (Bethany Joy Galeotti), whose husband —Lucas' brother Nathan (James Lafferty) — has gone missing. Even though Murray played Lucas for so many years, he says that stepping back into the role wasn't easy. "I've spent the last few years working with some great mentors, people and teachers, going to different theater classes and learning about what you're trying to say and how you represent each of those feelings," he says. "Lucas was just very simple. He was the moral center of the show, so to step into that and to pull it all back into this very simple, very easy-going [character] — that was the challenge."

Murray and co-star Hilarie Burton both exited the CW series after Season 6. Although there have been only a few mentions of their characters Lucas and Peyton since their departure, Murray says he's envisioned what they've been up to and why they missed such milestone events as Brooke and Julian's wedding. "He's over in New Zealand. The kiwis are quite nice," Murray jokes.

What about those letters Haley writes him? "I decided that yes, he did [receive them], but we discover here that I haven't. So I guess I haven't." And the odd resemblance Lucas and Haley and Nathan's son Jamie share? "I have always said, 'Dude, that's my kid. Where the hell was I 10 years ago?'"

See photos from One Tree Hill over the years

While Murray wouldn't spoil how Lucas makes his final exit, he says he hopes the fans enjoy one last visit from his character. "The fans have been the one thing that kept this show on the air for nine years, and they've been its heart and soul for the entire journey," he says. "That's the only thing I had on my mind."

One Tree Hill airs Wednesdays at 8/7c on The CW.