Her performance off-stage was flawless and saw her win over the crowd with her amazingly long legs. But Sienna Miller failed to receive the same reception from the tough Broadway critics following her turn in the opening night of her new stage show, After Miss Julie.

The 27-year-old actress stars as an aristocrat’s daughter in the play by Patrick Marber, a reworking of Strindberg’s 1888 classic Miss Julie. The play centers on Miller’s sexual encounter with her father’s valet, played by Jonny Lee Miller, another English Broadway debutant better known to Americans as the first Mr. Angelina Jolie.

New York Times reviewer Ben Brantley, the most influential on Broadway, while confessing that he was initially ‘rooting’ for Miller, wrote: ‘If Julie is written as clashing chords of conflicted impulses, Ms Miller plays them like a novice at a piano, plunking down each note loudly and individually.’

Ultimately, Brantley’s praise is limited to Miller’s “good diction, good posture and great legs. Commendable as these attributes are, they are of limited use in portraying a tautly wound, death-courting neurotic who is eaten alive by her own demons.”

Slightly more approving is Michael Kuchwara, who for the Associated Press also notes that Miller “looks sensational: blonde hair done up in a quintessential 1940s ‘do, her trim figure wrapped in a pert floral print dress that shows off her great legs. The very model of a seducer awaiting to commence seduction … And there is a relentless quality to Sienna Miller’s performance, not terribly subtle or vulnerable, but compelling in its obsessiveness.”

Terry Teachout, theatre critic for the Wall Street Journal also stuck the knife in. He said: ‘A model turned second-tier movie star, all she does is stalk around the stage striking vampy poses… she has no more business playing a classic stage role than I have posing for the cover of Vogue.’

Miller did receive support in some corners, however. The Associated Press described her theatrical offering as ‘compelling’ while the Chicago Tribune critic Chris Jones said she delivered a ‘gutsy’ performance that was ‘eminently watchable’.

In an interview published prior to the play’s opening night, Miller said: ‘No matter what happens, I’m never going to regret making this decision. To be here is a complete honor and a privilege.’

Reaction to Miller’s Broadway debut qualified as major news in her native England, where the news organizations tracked the reviews, as well as the fact that her former fiancé, Jude Law, and even a former boyfriend, Daniel Craig, are also on Broadway right now.

One thing all critics did agree on is that Sienna Miller knocked it out of the park at the after party. Wearing a $26,000 dress from Balmain’s Spring / Summer 2010 collection all eyes were on her and her toned stems as she rocked an edgy slashed cocktail dress. The super sexy sequined cut-out dress, distressed and torn all over, hit the runway mere weeks ago and Miller is the first celebrity to be photographed wearing it.