Cameron Diaz surprised a class of students at Stanford University on Thursday and one can only imagine what must have gone through those students’ heads when the Charlie’s Angels star walked in.

Diaz, 43, helped lead a lecture on environmentally friendly design as part of taping for an mtvU program called Stand-In, in which celebrities teach a class.

Cameron Diaz gets candid about all aspects of aging as a woman: https://t.co/tqRTRu0E88 pic.twitter.com/ZgacnnG3gx

— E! Online (@eonline) March 13, 2016

In similar fashion, Madonna lectured students at New York’s Hunter College last week.

Diaz has long been a champion for the environment and has served as a sidekick for friend and renowned environmental architect William McDonough, a consulting professor at Stanford.

“He’s very charismatic, captivating,” Diaz said of McDonough, who Time magazine once called “Hero for the Planet.” “Bill is one of those people who is thinking big, but is also producing.”

Check out @CameronDiaz' top health tips for women https://t.co/tH06EbxvrV pic.twitter.com/dFPkwWruez

— HELLO! (@hellomag) March 11, 2016

Needless to say, the students in the Stanford class pretty much lost it with gasps and giggles when Diaz interrupted the class right in the middle of McDonough’s lecture.

Cameron Diaz, who is starring in the recently released In Her Shoes, later took some time to snap selfies with the students on their cell phones.