Major news on Kate just weeks after she boosted nation with appearance at Trooping the Colour

Kate Middleton’s attendance at Trooping the Colour this past weekend likely took a “toll” on the royal, who is currently undergoing cancer treatment and had not made a public appearance since late last year.

The Princess of Wales, 42, who attended the annual event alongside Prince William and their young family, probably won’t return to the public eye “for a little while,” royal expert Katie Nicholl told Entertainment Tonight.

“The princess has this sort of swan-like quality about her — she’s sort of gliding on the surface — but beneath the water, I think often she’s paddling quite frantically,” said Nicholl.

Though “you would never have guessed” that Kate was undergoing chemotherapy, going by her “impeccable” looks alone, Nicholl surmised that Saturday’s appearance, which commemorated King Charles’ official birthday rather than his regular one, followed “a huge amount of preparation and time and effort and energy.”