Harry and Meghan will appear in public with William and Kate for the first time since the Sussexes opened up about the pressures of being in the spotlight in their tell-all African tour documentary.
The four will attend a service at the Royal Albert Hall commemorating all those who lost their lives in conflicts as part of the annual Royal British Legion Festival of Remembrance.
The event will also be attended by the Duchess of Cornwall, the Duke of York, the Earl and Countess of Wessex, the Princess Royal, the Duke and Duchess of Gloucester, the Duke of Kent and Vice Admiral Sir Tim Laurence.
In the ITV documentary Harry was asked about his relationship with his brother.
"Part of this role and part of this job and this family being under the pressure that it’s under... stuff happens," Harry said.
"But look we’re brothers. We’ll always be brothers."
The 'fab four' have rarely been seen in public together since they officially separated their royal households last March.
The service at the Royal Albert Hall will begin at 11am, although the Cenotaph will be open from 8am for members of the public who would like to be closer to the monument.
The festival will be broadcast on BBC One at 9pm.
On Sunday Prince Charles will lay a wreath at the Cenotaph as 10,000 people will march past the monument.
The Queen will view proceedings from the balcony of the Foreign and Commonwealth Office, as she did last year.
This year's event marks 75 years since notable battles of 1944 including Monte Cassino, Kohima and Imphal, D-Day and the collaboration of Commonwealth and Allied forces.
It will also celebrate the 100th anniversary of the Government Communications Headquarters and pay tribute to RFA Mounts Bay which delivered supplies and aid to the Bahamas after Hurricane Dorian this year.
The ceremony is hosted by the Royal British Legion and commemorates all those who lost their lives in conflicts.
