Sarah Michelle Gellar has shared a Cruel Intentions throwback picture as she wished her co-star Reese Witherspoon a happy birthday.

The duo both starred in the 1999 film, which was a modern day version of Dangerous Liaisons.

Gellar marked Witherspoon’s 42nd birthday by posting a snap of the duo dressed in school uniform in the film, alongside a more recent picture of them.

She captioned it: “Hmmmm @reesewitherspoon I know it’s your birthday, but I think we could try and pass for high school students!?! Just think about it. #happybirthday.”

Witherspoon, who is currently starring opposite Oprah Winfrey and Mindy Kaling in A Wrinkle In Time, also marked her birthday on Instagram.

She shared a photograph of her son Tennessee, five, presenting her with a birthday cake as she wrote: “Cake for breakfast, anyone? Thank you for all the sweet birthday wishes!

“Feeling so much love today! I’m one lucky gal (@draperjames even made me this birthday dress!) Thank you thank you!”

Jennifer Garner topped all the birthday wishes sent to Witherspoon on her special day by dressing in a marching band uniform and playing Happy Birthday To You on the saxophone.

She captioned the video, which she shared on Instagram: “Hey, @reesewitherspoon! I don’t know why you’re on my mind today….”

She added the hashtag: “#happybirthdayfriend.”