Alexia Russ is the owner of the Alexia Russ circus. She is a friend of Thea Stilton and an ally of the Stiltons in the episode "Clowning Around."

Russ is a very caring circus owner, taking care of her performers, especially the circus' star attraction, Augusto the Clown, which she viewed as "irreplaceable." However, she still fired Rapata for stealing from the cash box, seeing him as a disloyal thief. However, her other performers returned their loyalty to Russ, refusing to work for Rapata when he tried to start his own circus.

When the Alexia Russ Circus visited New Mouse City, the Stiltons visited her because she was a friend of Thea Stilton, training to be acrobats together. However, when they arrived, Russ and the performers were saddened by the disappearance of their clown, Augusto, believing he was kidnapped. While the Stiltons helped her investigate, Trap asked Russ to replace Augusto. Russ was hesitant at first, but when Trap accidentally made the other performers laugh, Russ agreed to let Trap perform if Augusto did not return.

Russ eventually helped the Stiltons identify the culprit as her former ringmaster, Ferner Rapata. As Rapata and his thugs kidnapped Trap as well, the Stiltons stopped Rapata and rescued both hostages, returning them to Russ' circus just before the performance.