Eva Allan and Zak Santiago guest star on Once Upon a Time tonight

Eva Allan and Zak Santiago are making an appearance in tonight's episode of Once Upon a Time, written by Jane Espenson.

"The Miller's Daughter" airs at 8 pm ET on ABC.

Press release and preview below.

CORA'S DESIRE TO TAKE RUMPLESTILTSKIN'S PLACE AS THE DARK ONE TAKES ONE STEP CLOSER TO BECOMING REALITY AS HE LAYS DYING, AND MARY MARGARET IS ONCE AGAIN TEMPTED BY DARK MAGIC, ON ABC'S "ONCE UPON A TIME"

Rose McGowan ("Charmed") Guest Stars as Younger Cora

"The Miller's Daughter" - Cora's desire to rid herself of Rumplestiltskin in order to take his place as The Dark One takes one step closer to becoming reality as she and Regina try to overpower a dying Mr. Gold, and Mary Margaret is once again tempted by dark magic. Meanwhile, in the fairytale land that was, Rumplestiltskin agrees to offer his services to a younger Cora - for a price - when the king calls her bluff and orders her to actually follow through on her boast of being able to spin straw into gold, on "Once Upon a Time," SUNDAY, MARCH 10 (8:00-9:00 p.m., ET) on the ABC Television Network.

"Once Upon a Time" stars Ginnifer Goodwin as Snow White/Mary Margaret, Jennifer Morrison as Emma Swan, Lana Parrilla as Evil Queen/Regina, Josh Dallas as Prince Charming/David, Emilie de Ravin as Belle, Colin O'Donoghue as Hook, Jared S. Gilmore as Henry Mills, Meghan Ory as Red Riding Hood/Ruby, and Robert Carlyle as Rumplestiltskin/Mr. Gold.

Guest starring are Barbara Hershey as Cora, Michael Raymond-James as Neal Cassidy, Rose McGowan as younger Cora, Gerry Rousseau as father, Joaquim de Almeida as King Xavier, Eva Allan as Princess Eva, Zak Santiago as Prince Henry and Sonequa Martin-Green as Tamara.

"The Miller's Daughter" was written by Jane Espenson and directed by Ralph Hemecker.

Live chat with Jane Espenson, The Walking Dead returns, interviews with Luc Roderique and William B. Davis

Three things to check out on TV tonight.

Jane Espenson's latest episode of Once Upon a Time, "Skin Deep," airs tonight at 8 pm ET. Jane will do a live Q&A on Twitter during the West Coast airing. From ABC's press release:

Fans of ABC's hit drama, "Once Upon a Time" will be able to submit questions and receive real-time responses from writer/consulting producer Jane Espenson, who will be up on Twitter at @JaneEspenson during the West Coast broadcast of the show on SUNDAY, FEBRUARY 12 from 8:00-9:00 p.m., PT. Espenson will also offer commentary and behind-the-scenes anecdotes about working on the show.

On Sunday's episode, "Skin Deep" - which was written by Espenson -- after Mr. Gold's house is robbed, Emma keeps a close eye on him when it looks like he wants to track down the criminal and dole out some vigilante justice as payback, and Valentine's Day finds Mary Margaret, Ruby and Ashley (Jessy Schram, "Falling Skies") having a girls' night out. Meanwhile, in the fairytale land that was, Belle (Emilie de Ravin, "Lost") agrees to a fateful deal to give up her freedom in order to save her town from the horrors of the Ogre war.

The Walking Dead (Bear McCreary scoring) returns with episode 2x08, "Nebraska," on AMC at 9/8c. Synopsis:

Rick and the others try to restore order in the aftermath of a terrible discovery. Hershel takes up an old habit and disappears, Rick and Glenn must follow him into town.

And Californication 5x06, "Love Song," directed by Eric Stoltz, airs at 10:30 pm on Showtime. Synopsis:

When Samurai Apocalypse hits a lyrical roadblock with his protege, he calls on the best writer he knows: Hank Moody, who unites with Kali to imbibe, bear his soul, and write a song that takes Hank back in time to an era when he, Karen and Charlie were happier and life was simpler before “A Crazy Little Thing Called Love.” But the present comes roaring back when Karen shows up at Hank’s door, worried that she made a mistake.

Eric is currently working on another episode of Glee. It's episode 3x15, "Big Brother," with Matt Bomer guest starring. Based on the Fox spring schedule and a few other things, it will air on April 10 at 8 pm.

New interview with Sasha Roiz and the weekend monster update

Let's start the weekly round-up with Grimm.

Grimm's ratings dropped a little this week, but the show still won the 18-49 demo in its timeslot, finishing ahead of CSI: NY, Fringe and Supernatural, and rising by a full frakking ratings point (1.8) after Chuck (0.8). Wake up, Chuck.

Hitfix visited the set in Portland recently and posted a lengthy report. Here is a snippet:

Sasha Roiz on how his character will develop later in the series: "I’m not a Grimm descendent, but I'm a descendent of a long line that dates back just as Grimm does and we have a bit of a history and a past, so my line is a royal line and that will slowly unfold throughout the series."

Collider has a longer interview with Sasha and Reggie Lee (more at the link):

It’s nice to see your character – like the main character – has the duality.
ROIZ: My character’s more seasoned in the fantastical world, a bit of a player, and he’s aware of the Grimm, but no one seems aware of who I am, except the people I want to be aware. It’s fun, and as we continue, there are always new things that are being developed. We don’t know where they’re going. We have a sense of the character, he comes from royal descent, his family has had ties for centuries and so on, and with every episode a little bit more is added to that story.

It feels like there’s a greater universe that will be fun to explore, but the show’s also a procedural.
LEE: It is that more than anything else, and you’ll see as we go on it remains a procedural, so the mythological elements are backburnered. I think they’ll come out eventually.

ROIZ: From what we’ve been told if there’s a back nine, that’s something we’ll explore but for now it’s more self-contained episodes.

The teaser for next week's episode, "BeeWare" (Friday, 9 pm, NBC), is embedded below. Nana Visitor (Deep Space Nine, BSG, Torchwood) guest stars.