In an interview, the actress said her friend Diaz was quitting the profession, triggering a flood of news stories.
She has since posted a message on Twitter explaining it was all a joke and quipped that she was now retiring from her position as Diaz’s spokeswoman.
She wrote: “BREAKING NEWS.
“Guys please, I was making a joke in an interview. CAMERON DIAZ is NOT retiring from ANYTHING.
“And for more breaking news: I am NOW retiring from being Cameron Diaz’s spokesperson.”
Blair and Diaz co-starred in The Sweetest Thing in 2002.
Blair said on Instagram: “I have had some inquiries related to an interview I did.
“In response to if the girls were gonna do a #sweetesthing part deux. I jokingly said #camerondiaz was retired.
“But I did brag about having lunch with her. Who wouldn’t?”
Diaz, 45, last appeared on the big screen in the remake of Annie in 2014.