The fan said: “I have it in my house! I don’t have it on me.”
A delighted Erivo then asked: “May I have it back, please? I thought I lost it forever.”
The actor, her team and Clara made arrangements to get the hat back to Erivo, who said: “Can we please get this lady’s number? You lifesaver.”
In less than 24 hours, more than five million people watched the video and over 1000 people have commented on the clip.
One TikTok user wrote: “This is so cute im glad you found her and were able to make arrangements to get it back to her! (sic)”
A second person said: “This is lovely … I’m hoping she rewards their honesty with kindness.”
And a third viewer said: “This is just so adorable. Humans being humans.”
Erivo reprises her role of Elphaba in Wicked: for Good, which is being released in New Zealand on November 20.
The sequel, which is based on the second half of the Broadway musical, Wicked, picks up after the events of the first film, and follows Elphaba as she discovers the Wizard of Oz (Jeff Goldblum) has been lying to the people of Oz about his powers and has turned her into a public enemy.
Eventually, Glinda (Grande) is forced to choose between her best friend and the Wizard of Oz.
The movie also stars Jonathan Bailey, 37, as Prince Fiyero, Michelle Yeoh, 63, as Madame Morrible, Ethan Slater, 33, as Boq and Colman Domingo, 55, as the Cowardly Lion.