Unboxed: Spending watchdog to investigate government's £120m arts festival
The National Audit Office (NAO) is to examine the delivery and value for money of the Unboxed festival.
It comes after the chair of a parliamentary committee called for an investigation into the £120m arts festival, criticising it as an "excessive waste of money".
The Department for Digital, Culture, Media and Sport said: "We do not agree with the select committee's views."
Unboxed was announced in 2018 by then prime minister Theresa May.
The UK-wide free event, which began in March and will run until November, features 10 projects highlighting science, technology, engineering, the arts and mathematics.
But the government's "celebration of creativity" was soon dubbed the Festival of Brexit, and has since had its visitor numbers questioned.
In late August, an article published in parliament's The House magazine claimed suggested there had been fewer than 240,000 visitors, despite a proposed target of 66 million.
However Unboxed told the BBC on Tuesday that "the numbers reported misrepresent the public engagement with Unboxed, and reflect attendance at only eight of the 107 physical locations from within the programme".
Last month, Unboxed chief creative officer Martin Green told the BBC the festival was "absolutely value for money".
The DCMS said on Tuesday that "more than four million people have engaged in Unboxed programming so far, and these numbers are set to rise further".
Conservative MP Julian Knight, chair of the DCMS select committee, which holds the government department to account, has questioned the money spent on the festival "during a cost of living crisis".
This prompted him to ask the NAO, the UK's independent public spending watchdog, to investigate.
In a letter published on Tuesday, the NAO's comptroller and auditor general Gareth Davies, confirmed that the Unboxed organisers and government would now come under greater scrutiny over the event.
"I propose in in the coming months to publish a short, focused report on Unboxed which could act as the basis for future questioning during a committee session with DCMS," Mr Davies wrote.
He added he expected they should be able to report on the costs and benefits associated with the festival, along with its management and planning work - including forecasting of visitor numbers.
Mr Knight told BBC Radio 4's Today programme the event was "unfortunately a monumental waste of money".
"And it's something we've warned about," he added. "And actually even within the department [it] was something that effectively they felt as if it was going off the rails. But no-one said, 'Stop, let's reassess. And if necessary, let's cancel.'"
However the DCMS responded by saying Unboxed had "helped open up access to arts and culture across the country with an inclusive and ground-breaking programme of live and digital events, designed to bring people together and delivered in partnership with the devolved nations of the UK.".
Unboxed added that its commissions have been presented in "more than 100 towns, cities and villages, engaged millions across live and digital and employed thousands of creatives around the UK".
Features of the festival include the See Monster installation in Weston-super-Mare - intended to promote the conversation about climate change - and Birmingham's PoliNations, as well as the About Us installation at Paisley Abbey in Scotland.
Unboxed organisers have not yet released official visitor numbers, but Mr Green told BBC Culture correspondent Katie Razzall last month that "millions" of people had engaged with it in person, and that he was "very confident" the festival would hit its visitor targets.
In June, the government said in response to its report on major cultural and sporting events that it disagreed with the committee's assessment of Unboxed, insisting it was "being promoted globally".