Treasury select committee chair Nicky Morgan had earlier today asked the NAO to probe the payment, put by prime minister Theresa May at £35-39bn.
NAO head Amyas Morse said he “intends to report on the main elements of the financial settlement with the EU”.
A spokesman said work was in hand and was expected to be put to Parliament before it rises for Easter.
Morgan, a Conservative former education secretary, said: "I welcome the NAO's commitment to examine the UK's withdrawal payment to the EU.
“This will provide assurance to Parliament over whether or not the so-called divorce bill is reasonable"
Morse appeared before Morgan’s committee in November and said that if asked to examine the ‘divorce’ bill “my thinking is that we would approach it quite like a normal large transactional deal, where you examine all the elements in it and then look at how they combine for reasonableness and range of value.
“It is quite familiar to people in the financial sector”.
Chancellor Philip Hammond said this week that further analyses of the impact of Brexit would be kept secret.
