The civil marriage of Prince Charles and Camilla Parker Bowles is legal, the lord chancellor has said.
The wedding is due to take place on 8 April in Windsor Guildhall
In a written statement to the House of Lords, Lord Falconer said he was satisfied such a ceremony was in accordance with the Marriage Act 1949.
Lord Falconer's statement was in response to claims first reported by the BBC's Panorama programme that Royals could not have civil weddings.
On Tuesday the Queen said she would not attend the 8 April civil ceremony.
Downing Street has said it will only comment on the issue of the prime minister's attendance in the event an invitation has been sent.
The lord chancellor - who is currently out of the country - said in his statement that the government was aware that in the past different views had been taken, but that they had been "overcautious".
"We are clear that the interpretation I have set out in this statement is correct," he wrote.
On Monday Sir Nicholas Lyell, a former attorney general, suggested emergency legislation may be needed to clarify the legal position before the wedding.
He said he felt "disquiet" about the government's advice to the Queen and that he believed the 1949 Marriage Act, which updated the law on civil marriages in England, excluded the Royal Family.
And he maintained on Thursday Lord Falconer's position risked being regarded as "tenuous", saying the government should introduce a short bill to clear up the matter.
"The Human Rights Act does help but it is an unsatisfactory state of affairs when the legality of the marriage of the Prince of Wales has to depend on that," he said.
After it was revealed the Queen would not attend the marriage, both Buckingham Palace and Clarence House were quick to deny her non-attendance was a snub to her eldest son and Mrs Parker Bowles, saying it was intended to keep the civil ceremony at Windsor's Guildhall a low-key affair.
Commentators have also suggested that, as Supreme Head of the Church of England, the Queen would have been reluctant to attend a civil marriage.
Public reaction to continuing Charles and Camilla controversy
However, the Queen and Duke of Edinburgh will attend a blessing by the Archbishop of Canterbury at St George's Chapel, Windsor Castle, followed by a reception.
"The Queen's prime concern is that the civil ceremony should be as low key as possible, in line with the couple's wishes.
"Clearly if the Queen were to attend, the occasion would no longer be, by definition, low key," said a Buckingham Palace spokeswoman.
Downing Street said the Cabinet had sent their warmest congratulations to the couple but had not yet discussed whether to send a present.