It couldn't be more perfect that Meghan appeared in the 2012 Castle episode "Once Upon a Crime," all about princesses and fairytales. Six years before marrying Prince Harry, the Suits star played serial killer Charlotte Boyd. Fortunately, mystery writer Rick Castle (Nathan Fillion) foiled her evil plans. The clue that tipped him off? The special way Charlotte tied the bow of her Sleeping Beauty costume.
In "Poof! You're Dead," the legendary Chadwick portrayed magician Chuck Russell, who tries to fool Detective Beckett (Stana Katic) with a disappearing act so he doesn't have to speak with police. She uncovers his trick and iconically declares, "Alakazam, jackass." The episode aired in 2011, seven years before Chadwick starred as T'Challa in Black Panther. Two years later, he tragically died of colon cancer.
Before spending six years playing Alex Vause on Orange Is the New Black, Laura appeared as Natalie Rhodes on one episode of Castle in 2011. Her character was a famous movie star vying for the role of Nikki Heat (Castle's sexy-smart character based on Beckett), who even tried to strike up a romantic relationship with the author in the name of "research."
David Foster's daughter (and Katharine McPhee's stepdaughter) took on the role of Sky Blue in the 2009 episode "Famous Last Words," portraying the younger sister of slain singer Hayley Blue (played by Brianna Haynes).
The Charmed star got a bit flirty with Nathan in the 2010 episode "A Rose for Everafter." Alyssa's character, Kyra Blaine, got tangled up in a murder on her wedding day—and her ex, Castle, was there to comfort her and find her bridesmaid's killer.
Dr. April Kepner? Is that you? Just one year before starring on Grey's Anatomy in 2010, Sarah took on a role in a different ABC drama. She played murderous babysitter Chloe Richardson in "Nanny McDead," which includes too many cheating plot lines to count.
Jane was quite the scam artist in the 2011 episode "One Life to Lose," about the death of writer Sarah Cutler, who worked on a fictional soap opera called Temptation Lane. The Kominsky Method actress played character Gloria Chambers, who pretended to be the victim's mom in order to get money in her will—but she wasn't the killer.
In the same episode, it turned out that Sarah was killed by her own assistant, Reese Harmon, who literally gave her the ax in order to cover up her plagiarism scheme. None other than Tina took on the role of Reese, after starring as Mac in Veronica Mars and Deb in Napoleon Dynamite.
Don't mess with Dana! The Desperate Housewives star stepped into the role of FBI Special Agent Jordan Shaw in season two of Castle, apprehending serial killer Scott Dunn (Dameon Clarke) in a dramatic two-part episode. In "Tick, Tick, Tick..." and "Boom!" she helps catch the mastermind, who becomes obsessed with Beckett after reading Castle's book Heat Wave.
It's no coincidence Dana went on to land her own crime show, Body of Proof, which ran from 2011 to 2013.
Lady Gaga's ex stepped into the spotlight on Castle alongside Meghan Markle, playing the brother-in-law of one of her victims. You'll recognize Taylor from the movies The Other Woman and Zero Dark Thirty, as well as the shows The Vampire Diaries (on which he played Mason Lockwood) and Chicago Fire (as Kelly Severide).