Professor Stephen Hawking is used to having famous faces attend his lectures, but his fan club welcomed a royal member on Wednesday (Aug. 24) when Princess Mary attended his "Quantum Black Holes" presentation at the Koncerthuset in Denmark.

TAP FOR GALLERY Princess Mary met Professor Hawking following the lecture.

Dressed in a pink summery dress and grey cardigan, the crown princess watched in awe as Stephen shared his wisdom with the 1800-strong audience. Following the lecture, Mary headed backstage to have a personal meet-and-greet with the legendary genius.

Senior members of Denmark's royal family headed to Rio for the Olympics.

It's been a busy summer for the 44-year-old, who returned to royal duties after spending some time at the Rio Olympics with her husband Crown Prince Frederik. While in Brazil, the couple cheered on the Danish team from the stands and even visited with athletes in between events. Equestrian Catherine Dufour shared a picture of the royal posing with one of her horses in the paddock.

Olympian Catherine Dufour shared a picture of Princess Mary on Instagram.

Denmark's Prince Joachim and Princess Marie were also in Brazil and were spotted exploring the world-famous Iguazu Falls en route to Rio.

The fashionable mother of four attended the opening show at Copenhagen Fashion Week.

After returning home from Rio, Mary made a series of fashionable appearances including the opening day of Copenhagen's fashion week. She looked FROW-ready in a white dress and tan coat as she made her way into the Fonnesbech show on Aug. 10.