Jaimie Alexander and Clark Gregg Jaimie Alexander and Clark Gregg

Lady Sif is coming to Midgard!

Jaimie Alexander will make her Agents of S.H.I.E.L.D. debut on Tuesday (8/7c, ABC) as her Thor character Lady Sif attempts to track down Asgardian foe Lorelei (Elena Satine), the seductress who made a brief cameo at the end of last week's episode. Lorelei will team with the Agents of S.H.I.E.L.D. to complete her mission, even finding a kinship with someone among the group. TVGuide.com turned to Alexander to get the scoop on how her guest spot came together, Sif and Lorelei's rivalry and what Sif's arrival means for Coulson's (Clark Gregg) secret:

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How did this crossover come together?
Jaimie Alexander:
I have to give all the credit mostly to Clark Gregg. We had seen each other at a party about two weeks before I got the offer to come on Agents of S.H.I.E.L.D. He asked me — as he put it — hypothetically if I'd be interested in doing some sort of crossover. I said, 'Absolutely, I think it would be a lot of fun and I'd totally be game for it.' Of course, two weeks later I got a call. I was like, 'Ah, Clark buttered me up.' But I didn't have to be buttered up.

What kind of dynamic do Lorelei and Lady Sif have?
Alexander: It's yin and yang. Lorelei is extremely selfish, and Sif is completely selfless. They can't see eye to eye on anything. She knows how dangerous Lorelei is and what she could possibly do to Earth. She's sent on a mission to retrieve her and bring her back to Asgard. When she gets there, she knows she's on someone else's turf. Out of respect, she enlists the help of Agents of S.H.I.E.L.D. to track down Lorelei to get her back to Asgard.

How does the team take to Lady Sif?
Alexander: It's a little bit of a fish-out-of-water experience for Sif and for the team. You've got somebody from another world and you're collaborating with them. It's something that doesn't happen often. At first, they think she's a threat. She clearly walks around with a sword and a shield and is very skilled at combat, but because of Agent Coulson vouching for her, the agents accept her. It's the same if they were to come to Asgard. When Thor (Chris Hemsworth) says they're OK, they're OK. So when Agent Coulson says this Asgardian is OK, she's OK. Essentially, Agent Coulson is the Thor of Agents of S.H.I.E.L.D. I know he's going to fan-boy over that one. [Laughs]

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Thor believes Agent Coulson to be dead, so that puts Sif in an interesting position. Will she have to keep his status a secret?
All I can say to that is that it is absolutely addressed in the episode.

Sif also arrives after Coulson has discovered the truth about what saved him. Might he look to Sif for answers?
All these things are absolutely addressed in the episode, but I can't tell you the outcome. But know that you will receive some satisfaction in this episode.

Lorelei has very persuasive powers and it appears that Ward (Brett Dalton) falls under her spell. What lengths will the team have to go to save him?
I can't say that he actually falls under her spell or not because it's a bit of an illusion, if you will, but I will say that she really manipulates quite a few men in this episode. It's an epidemic of sorts. The fact that Sif has come personally down to Earth to retrieve her and she has a strong hatred towards Lorelei, both Sif and the Agents of S.H.I.E.L.D. go to extreme lengths to get her to stop and to capture her. A lot of sh-- hit the fan. It messes with quite a few people's souls, including Sif.

What is it like facing her foe on an entirely different planet?
Sif's definitely out of her element, but the one thing that rings true is that she's going to capture Lorelei. Failure is not an option for her. She personally took it upon herself to come to Earth to retrieve Lorelei. It wasn't Volstagg (Ray Stevenson), it wasn't Fandral (Zachary Levi), it's wasn't Hogun (Tadanobu Asano), it was Sif. It's equally as personal a mission than it is just for the King (Anthony Hopkins).

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Is it a possibility we could see Sif return in the future?
Everything is possible. If there's a strong reason why she would come back, I would love to see her come back. She's asked for their help. It would be nice to return the favor to the Agents of S.H.I.E.L.D. If they ever needed help, they could absolutely call on Sif.

What was the best part of portraying this role on the small screen?
Just the fact that we get to explore and learn a lot more about Sif. There are things I took from the comic books, like mannerirms, that I put in there because I know I've had the request to get to know Sif more, what she likes and what's her everyday life like? You definitely get to see a very strong, compassionate side to Sif and a similarity between her and Melinda May (Ming-Na Wen), which is very fun to explore. There are so many parallels between the Asgardians and the Agents of S.H.I.E.L.D. It's a lot of the same dynamic. Sif could very much relate to Melinda May and vice versa.

Do they find a kinship?
Absolutely. As with anything, if you're working with a group of people for a certain amount of time, you get to know all sides of them and you learn something you don't expect. You definitely get to see that in this episode.

Speaking of getting to know Sif, people have been dying to see the dynamic between Sif and Thor explored more. Are you hoping to see that in the third Thor film?
All I know about the third installment is that there's a writer attached. They purposely don't tell us things so that we don't spill the beans. Rightly so, they shouldn't tell me because I geek out over stuff and would say something, and then I'll see a little red dot on my chest and there's a Marvel sniper. I would love, obviously, for that to be explored more. We've shot scenes that do explore it more, but they don't make it into the film because of certain storylines and crossover aspects, and also for timing. It's anybody's guess, but that would definitely be a fun thing to explore.

Agents of S.H.I.E.L.D. airs Tuesdays at 8/7c on ABC. Are you excited to see Lady Sif on Agents of S.H.I.E.L.D.?