Labour leader Jeremy Corbyn has been sworn in to the Privy Council, the historic group which advises monarchs.
The lifelong republican officially joined the council in front of the Queen at Buckingham Palace.
Labour did not confirm whether he knelt and kissed the hand of the Queen - a traditional part of the swearing-in ceremony.
But speaking before the event, Mr Corbyn said: "I don't expect to be kneeling at all, no."
"I expect to be nominated to the Privy Council and that's it," he told ITV News.
A Labour press officer said after the ceremony that Mr Corbyn had "complied with the normal processes".
The court circular from Buckingham Palace on Thursday reported that: "This day Jeremy Corbyn was, by Her Majesty's command, admitted, on affirmation, as a Member of Her Majesty's Most Honourable Privy Council and took his place at the Board accordingly."
The Labour leader missed the first meeting of the Privy Council in October, citing prior engagements.
The Labour Party denied that this was a snub, pointing out that David Cameron took three months to be sworn in to the council after becoming Conservative leader.
What is the Privy Council?
- The Privy Council dates from the court of the Norman kings
- There were separate Privy Councils in England and Scotland prior to the 1707 Act of Union
- It convenes, on average, about once a month - and has met six times so far this year
- The quorum required for each meeting, with a few exceptions, is three plus the Lord President (currently Chris Grayling)
The Privy Council's role is to advise the monarch of the day in carrying out their duties, such as the exercise of prerogative powers and other functions assigned to them by Acts of Parliament.
Much of its business is routine and is concerned with obtaining the monarch's formal approval of orders which have already been discussed and approved by ministers or arranging for the issuing of royal proclamations. Queen Anne was the last monarch to refuse an order.
Now Mr Corbyn is a privy counsellor he will be able to use the title Right Honourable.
Opposition leaders can receive confidential briefings from the security services through their membership of the group.
Ahead of the meeting, Mr Corbyn said it would be "a very normal kind of occasion, and I will be appointed [to the council]".
When asked in September if he would kneel to the Queen during the swearing-in ceremony, Mr Corbyn said he did not know that was involved, adding that there were some things that "ought to change in our society, maybe that's one of them".