Kaley Cuoco
Kaley Cuoco regularly takes Polaroid photos on the set of “Big Bang Theory” Season 11 and shares it on Instagram. Pictured: Cuoco attends the premiere of 20th Century Fox’s “Why Him?” at Regency Bruin Theater on Dec. 17, 2016 in Westwood, California. Getty Images/Mike Windle

Kaley Cuoco recently shared two polaroid photos of herself with her “Big Bang Theory” co-stars ahead of Thursday’s episode.

On her Instagram account, Cuoco revealed that episode 9 will feature a flashback to a time when her character, Penny, and Bernadette (Melissa Rauch) were still working at the Cheesecake Factory. In her caption, Cuoco expressed her happiness when she found out that the costume she wore years ago could still fit her.

In the second snap, Cuoco’s male co-stars, Johnny Galecki, Jim Parsons, Simon Helberg and Kunal Nayyar, are all sitting together on the set of the hit CBS series. Cuoco called the four actors, “My guys.”

Ever week, “The Wedding Ringer” star shares Polaroid photos from the set of the show that were taken while filming a particular episode. Cuoco has used the hashtag “Kaley’s Polaroids” to commemorate their time on set.

Meanwhile, this week’s episode, titled “The Bitcoin Entanglement,” featured a flashback video from seven years ago. In the clip, a secret about Leonard (Galecki) and Penny’s relationship was revealed. A few years ago, Penny decided to give Zack (Brian Thomas Smith) the laptop that Leonard gave to her.

Penny and Leonard were not in good terms at that time so she decided to get rid of the one thing that reminded her of him. Penny asked Zack for the laptop back, and he told her that he still had it.

Leonard was upset at what Penny did, but he was also flattered when Zack told him that Penny kept talking about Leonard. Zack showed Leonard a video of Penny gushing about Leonard, which proved how much she really loved him even then.

Elsewhere in the episode, the guys were surprised when they learned that a Bitcoin is now valued at $5,000. They mined one several years ago, and they went to search for it. Howard (Helberg) looked for the Bitcoin in his laptop, but didn’t find it. Leonard offered to lend Howard his computer, but he gave it to Penny years ago.

When they finally recovered it from Zack, they discovered that the Bitcoin folder was empty. It was later on revealed that Sheldon had a copy of it.

“Big Bang Theory” Season 11 airs Thursdays at 8 p.m. EST on CBS.