The new Melania Trump documentary beat box office predictions to earn more than $7m (£5.1m) at US cinemas in its opening weekend.

The film follows the US First Lady and reportedly became the most expensive documentary ever, with Amazon spending $40m (£29m) on the rights and a further $35m (£25.5m) on marketing.

It was expected to generate in the region of $5m (£3.7m) in its first weekend, but its actual takings are "a huge start for a documentary", Variety said, and "no one saw that coming", according to the Hollywood Reporter.

But it will need to earn much more to break even, with some suggesting Amazon's deal has more to do with politics than immediate financial considerations.

Melania claimed the film has been "loved by all", citing the A CinemaScore rating it had received in a survey of those who had gone to see it.

It also has an overwhelmingly positive 99% audience score on review aggregator Rotten Tomatoes - but there is a big gulf between that and its 10% score from film critics.

Variety's Owen Gleiberman said the documentary was "so orchestrated and airbrushed and stage-managed that it barely rises to the level of a shameless infomercial", while Empire's reviewer William Thomas called it "an obsequious, ring-kissing portrait of the current US administration, dressed in gauche, glossy reality-TV clothing".

The London Evening Standard's three-star review from Melanie McDonagh was something of an outlier, acknowledging the "scathing" reviews" but adding that "those who accept what it's about - Melania, curated by Melania (this may be mostly political nerds), it's rather fascinating."

Amazon's motives for paying such a high price have been questioned, even considering the film's strong opening performance.

"Amazon MGM Studios plunked down $40 million for worldwide licensing rights in a deal widely seen as a move to cozy up to the White House," according to the Hollywood Reporter.

Last week, the New York Times said much of Hollywood was asking "whether Amazon's push is anything more than the company's attempt to ingratiate itself with President Trump".

When asked for comment about its promotion of the movie by the newspaper, Amazon repeated a statement it had released in the past: "We licensed the film for one reason and one reason only - because we think customers are going to love it."

Amazon's deal for the film also included the rights to a follow-up series about Melania.

Amazon MGM head of domestic theatrical distribution Kevin Wilson told Variety: "We're very encouraged by the strong start and positive audience response, with early box office for Melania exceeding our expectations.

"This momentum is an important first step in what we see as a long-tail lifecycle for both the film and the forthcoming docu-series, extending well beyond the theatrical window and into what we believe will be a significant run for both on our [streaming] service."

The film particularly overperformed with older white women in locations like Texas and Florida, which are pro-Trump heartlands.

It was also released in UK cinemas, but box office figures are not yet available.

It is directed by Brett Ratner - his first project since he was accused of sexual misconduct in 2017, which he denied. Over the weekend, photos of him emerged with late sex offender Jeffrey Epstein and two women.

There is no indication of wrongdoing from the files. The BBC contacted Ratner's representative on Sunday for comment.