Prince Harry has asked his brother Prince William to be his best man at his wedding to Meghan Markle, Kensington Palace has said.
Prince Harry had been the Duke of Cambridge's best man at his wedding to Kate Middleton in 2011.
The wedding will take place at St George's Chapel, Windsor, on 19 May.
More than 600 guests have been invited to the ceremony with 1,000 members of the public being welcomed to the grounds of Windsor Castle.
A further 200 guests - including the Spice Girls - have been invited to the couple's evening reception.
In a statement, Kensington Palace said: "The Duke of Cambridge is honoured to have been asked, and is very much looking forward to supporting his brother."
The palace also tweeted a picture of the pair of Princes when they were boys wearing police helmets.
Earlier this week, the palace announced the list of musicians who will be playing at the wedding.
They include a gospel choir and 19-year-old cellist Sheku Kanneh-Mason, who won the 2016 BBC's Young Musician.
Before his brother's wedding in 2011, Prince Harry said his best man's speech would "dig (Prince William) in the ribs a few times and embarrass him" and "make him lose some hair".
In an interview with Rio Ferdinand in January, Prince William joked that his brother had not yet asked him to be the best man and "it could be a sensitive issue".
The May wedding will be the second time within a month to see Markle as a bride.
The actor's exit from the series Suits was shown on TV on Wednesday with her character getting married.
Meanwhile, the wait continues for the name of Prince William and Catherine's third child who was born on Monday to be announced.
The new prince weighed 8lb 7oz and is fifth in line to the throne.