Princess Charlene always looks so stylish and as she made a public appearance on Sunday, royal watchers were quick to compliment her on her gorgeous outfit.
The mother-of-two joined her husband, Prince Albert, at Monaco's Grand Prix, where Max Verstappen drove to victory.
Applauding as she watched him lift his trophy, the princess looked beautiful in a long, black sleeveless dress featuring an incredible detail.
The dress had subtle stripes in the hues of the rainbow which opened out towards the hem to reveal wider shocks of colour.
In contrast to her highlighted look at King Charles' coronation earlier this month, Charlene's hair was dark brown, cut in a flattering short style and she kept her makeup light.
On Twitter, viewers were quick to praise the royal's outfit, with one writing: "PRINCESS CHARLENE IN THAT RAINBOW DRESS!!! #MonacoGP."
Others added: "Loving HSH Princess Charlene's dress at the @F1 #MonacoGP…," "Loving Princess Charlene's dress. Subtle, but it's there [rainbow emoji]," "Princess Charlene said happy pride #MonacoGP," and: "Princess Charlene's dress slaps".
Princess Charlene and Prince Albert are huge fans of the Monaco Grand Prix, and always attend the event. Last year's was the first Formula 1 meeting that the princess attended since recovering from the ENT infection that left her stranded in South Africa for most of the previous year.
Motorsport is clearly one of Charlene's passions and her first public appearance following her health battle was at the Monaco E-Prix, which is for electric vehicles.
The couple were joined at last year's Grand Prix by their children, twins Prince Jacques and Princess Gabriella, eight, although the loud noises from the crowds and cars proved to be a little too much to handle for the young royals with the pair snapped covering their ears, prompting the doting mum to comfort her children.
Last month, Charlene and her husband stepped out into the limelight alongside their twins, as they attended the Sainte Devote Rugby Tournament.
Charlene was the protective mum as ever, wrapping her arms around her two children as they watched the match together, with young Jacques getting excited during the action.
Charlene also chatted with some of the players who took part, before the royal couple presented the winning team with the trophy.
The couple even had a surprise twinning moment with their outfits with the royal couple both wearing the same blazer as they headed to the stands with their young children.
Charlene also wore a white top with matching trousers and a stylish pair of sunglasses, while Albert completed his ensemble with a shirt and trousers.
The tournament is an annual event in Monaco and supported by the Royal Family as under-12s from across the globe head to the principality to compete in a day filled with activities.
The family's outing came just days after Charlene and Albert put on a loved-up display as they were seen in the crowds of a tennis tournament alongside Jacques and Gabriella.
Albert and Charlene, who will celebrate their 12th wedding anniversary in July, chatted and smiled with one another as they watched the action between Denmark's Holger Rune and Russia's Andrey Rublev.
Want to keep up to date with the latest stories? Sign up to our HELLO! Newsletters today.