The Los Angeles-born star looked impeccably stylish in a navy asymmetric dress by Antonio Berardi and white blazer as she proudly applauded from the terrace.
Despite initially trying to keep their romance under wraps, the bold outing at a formal occasion shows that their relationship is going from strength to strength.
Harry was also joined by his brother, the Duke of Cambridge, for the fun and games at the lavish Coworth Park polo club in Berkshire.
The youngest Prince looked in his element during the first day of the competition on the Berkshire grounds, in front of celebrity guests including Oscar winner Eddie Redmayne, dancer Darcey Bussell and actor Matt Smith.
Meghan and Harry’s outing comes ahead of rumours that the actress will attend Pippa Middleton’s wedding on May 20 – despite reports that Pippa is decreeing a ‘no ring, no bring’ policy in regard to plus ones.
Despite filming in Canada, sources tell the Mail that she has taken a week’s holiday and is expected to attend the ceremony and the reception.
Her appearance would fuel speculation that there may be another wedding on the cards after Pippa’s. Kensington Palace refused to comment yesterday.