It’s not just beauty that’s only skin deep in The Danish Girl.

Adapted from David Ebershoff’s 2000 novel, “The Danish Girl” brings us a fictionalised account of the life of Lili Elbe, one of the first people in the world to undergo gender reassignment surgery. The film, like its source novel, is much less an exploration of the prejudices and societal attitude towards sexuality and transgender issues in 1930s Europe than it is an examination of the evolution of an unconditionally loving marriage under extraordinary circumstance.

When portrait artist Gerda Wegener (Alicia Vikander) asks her celebrated landscape painter husband Einar (Eddie Redmayne) to stand in for a female model who is running late, it awakens an initially hesitant but ultimately unstoppable emergence of Lili and the abandonment of life as Einar.

Much has been made of the departures from the actual life of Lili Elbe in this heavily dramatized and romanticized tale, but many of these changes are not the work of the film makers. This is an adaptation of a novel which was itself largely a work of fiction, albeit based on true events. The most significant – and some would say egregious – change is the heteronormalisation of Gerda’s character although at least the film allowed her to retain her real nationality and did not Americanise her as the novel did. In real life, Gerda was at least bisexual and her relationship with Einar/ Lili was closer to that of sisters/ friends than spouses and lovers. This is completely ignored in the film, as is a large body of her work as an artist. Taken as a work of fiction, though, this is an absorbing and poignant romantic drama studying the effect the transition has on the two people it most directly affects.

Eddie Redmayne is, of course, excellent as Einar Wegener / Lili Elbe, predictably excellent even. While he’s very convincing as Lili, there’s a repetitive nature to his mannerisms and physicality which starts to wear thin after a while. It’s still a very good performance, and the subtle intricacy of it is revealed in an impressive sequence where he plays Lili trying to pretend to still be Einar. While Redmayne will undoubtedly attract applause for yet another intimate and immersive performance, it’s actually his co-star who really deserves the plaudits.

Deprived of the cosmetically transformative costumes, make-up and gimmickry afforded Redmayne, Vikander delivers on her promising breakthrough last year with a powerfully honest and emotionally naked performance as the wife who loves unconditionally yet struggles to come to terms with what is happening to the person she loves. The two leads are joined by Ben Wishaw as Henrik, an artist with a romantic interest in Lili and Matthias Schoenaerts (who must surely be a shoe-in for any forthcoming Vladimir Putin biopics) as Hans Axgil, a Paris Art Dealer and Einar’s childhood friend.

Beautiful to look at and blessed with fine performances all around, there’s still something lacking from “The Danish Girl”. It struggles to get under the skin of its characters, only ever superficially engaging with its subject matter instead of coyly distracting us with a demure flutter of the eyelashes and a simpering smile.