Rachel Weisz is that rare combination of actress and star, the kind of performer equally at ease in offbeat arthouse films like “Youth” and “The Lobster” as well as big-budget movies like “The Bourne Legacy” and “Oz the Great and Powerful.” It has remained fitting that the 46-year-old British-born Weisz won a supporting actress Oscar for playing an enigmatic, predictably unpredictable woman in 2005’s “The Constant Gardener.”

So it also makes sense that in the new film “Complete Unknown,” directed and co-written by Joshua Marston, she plays a woman who reinvents herself every few years with an entirely new identity — and in the process has lost track of who she really is. She manipulates her way into the birthday dinner party of a man (Michael Shannon) who knew her before she set off on this wild life of adventure. Over a long evening, she begins to rediscover her true self.

Weisz can also be seen in “Denial,” which was directed by Mick Jackson and which had its world premiere as part of the Toronto International Film Festival. In the movie, based on a true story, Weisz plays Deborah Lipstadt, a noted American historian who was sued for libel in a British court by a Holocaust denier. Costarring Timothy Spall and Tom Wilkinson, the picture is part courtroom drama, part defense of history over conspiracy and conjecture.

Weisz is also in the new “The Light Between Oceans” and will soon be appearing at the Public Theater in New York in a production of “Plenty.” She recently found a few minutes to get on the phone to talk about this busy time.

Q: You have “Complete Unknown,” “The Light Between Oceans” and “Denial” coming out, and you’re going to be onstage in “Plenty.” From the outside, it seems like a lot of work. Does it feel that way to you?

A: “Denial” and the play are major commitments. The play has only been performed once in New York, in 1982; it was written in 1978, and it’s probably not performed very often because it’s such a challenging play.

It spans 20 years, and my character goes through huge transformations and mental breakdowns, and it’s a big ol’ journey. I’ve been in love with the play for many years, and I finally felt old enough to take it on. So that’s a real massive commitment.

“Denial,” which is coincidentally also written by David Hare, the same writer as the play, was an undertaking, because it was playing a real character, Deborah Lipstadt, who is from Queens and is just nothing like me. Physically, culturally, accent-ly, that was a real transformation. Those two things were challenging.

Q: What interested you about “Denial”?

A: I think it’s an important story, and she’s a very colorful character and a pain in the a- and no bull. She’s larger than life and not a shrinking violet. She’s complicated, she’s a lot of things.

I think David was inspired to write it really in response to Donald Trump. So people who are protected by the freedom of speech just lie and lie and lie and lie and lie and lie. There are situations where you can be held accountable for your lies, and this was one of them. There’s a difference between a fact and an opinion. And the movie proves that. I hope that it inspires anyone, particularly young people, to stand up to bigotry and this casual racism.

Q: There’s a sequence in the film that was shot at Auschwitz. What was it like to shoot there? Had you ever been there before?

A: It’s very hard to find the right words to describe it, because it’s not like anything I’ve ever experienced. I’ve never been to Auschwitz before and walking around it, going through the museum and seeing exactly what took place there, what struck me was the degree of organized, mechanized, industrialized … It was like the most efficient factory where nothing was left out.

I can understand a human in a fit of passion acting out in a visceral, primitive way, but this was not that. It was meticulously scientific. It’s the coldness of it that you can’t reconcile with being a human. I understand losing your temper, it’s terrible and wrong, but I understand it. But this makes your mind not able to compute it.