Jessica Biel Celebrates '7th Heaven's 21st Anniversary With Epic Flashback Photo

Jessica Biel will always be Mary Camden!
The 35-year-old actress took to Instagram on Saturday to celebrate the 21-year anniversary of 7th Heaven's premiere with an adorable throwback photo. 

"7th Heaven first aired 21 years ago today. Happy birthday, 7th Heaven- lemme buy you a drink. ?," Biel wrote alongside a flashback snap of herself and her on-screen sister, Beverley Mitchell. 

Mitchell also made an appearance in a behind-the-scenes shot Biel shared on Thursday, alongside their on-screen brother, Barry Watson. 

"Photo evidence I was rocking mom jeans way before I was actually a mom," the now-mom to 2-year-old son Silas captioned the photo. 

ET was with Biel and the rest of the 7th Heaven cast on set of the WB show's first season in 1996. Watch below.