Prince Harry has arrived at Hampton Court Palace for the charity concert the evening.
The Duke was swiftly offered a brolly as protection from the miserable weather.
During the evening Harry will welcome singer Rita Ora and Sentebale ambassador and spoken word artist, George the Poet - who will both perform to an audience of 3,000 people.
The charity was launched by the Duke of Sussex to support children affected by HIV in Lesotho and other parts of Southern Africa.
The concert will raise funds and awareness for Sentebale, the charity founded by Prince Harry and Prince Seeiso Bereng Seeiso in 2006.
The new dad is attending the event on his own this evening with wife Meghan Markle at home looking after baby Archie.
Earlier today the Duke and Duchess of Cambridge, in Cumbria, met a springer spaniel named after Harry.
The seven-month-old four-legged friend is a therapy dog for owner Kerry Irving, who uses his dogs to help others get outdoors to fight depression and poor mental health.
According to a royal source Meghan is breastfeeding Archie and Harry is dutifully helping out changing nappies.
The source told Elle that Harry wants to be as “involved as possible" and despite being exhausted he is “enjoying every minute of it.”
The couple are also reportedly taking Archie for long walks in the sprawling grounds of Frogmore Cottage.
