Who plays Lady Deadpool? Fan theories include Blake Lively and (of course) Taylor Swift

With Marvel Studios' blockbuster "Deadpool & Wolverine" hitting theaters Friday, many fans who saw the film's recent trailer are speculating about who plays the female version of the Merc with a Mouth, with guesses ranging from Taylor Swift to Blake Lively.

Toward the end of the final trailer for "Deadpool & Wolverine," released Friday on actor Ryan Reynolds' YouTube channel, a female donning the anti-hero's suit can be seen briefly. In Marvel Comics, the character is known as Lady Deadpool.

Reynolds, who plays Deadpool, appeared Monday on Jimmy Fallon's "The Tonight Show" and said the film does not "really have cameos as much as surprises." Before Reynolds could continue speaking, Fallon mumbled "Taylor Swift" multiple times.

Once Reynolds hears Fallon say the 14-time Grammy award-winning singer's name, he says, "I wish... she'd make a good Deadpool."

Is Taylor Swift in 'Deadpool & Wolverine?'

During a recent interview with E! News, Reynolds addressed the rumors of Swift appearing in 'Deadpool & Wolverine."

Need a break? Play the USA TODAY Daily Crossword Puzzle.

“I will say once and for all that the cameo thing with Taylor,” the actor told E! News, adding, “because she’s our friend—that is not in this film.”

Reynolds gave Swift her props and indicated − just like he did in his appearance on "The Tonight Show" − that she would be great in the role.

“I always do say that if anyone ever were to take over the role of Deadpool, actually Taylor would be very good,” Reynolds told the entertainment outlet. “Because that’s a superpower that I don’t know that she shows everyone too often: She’s one of the funniest people I’ve ever met.”

Is Blake Lively playing Lady Deadpool?

Blake Lively, who is Reynolds' wife, is fans' next bold prediction for who is playing Lady Deadpool. A recent Instagram post has only fueled these suspicions.

Lively shared a post on Friday showing her kissing Reynolds, who is in the full Deadpool costume. The caption for the post says, "Brb I’m buying milky pens to write your name on my hand @vancityreynolds."

"MY WORD… it’s hard not to encourage my ladies to spot all the ways we’ve influenced @deadpoolmovie I’ve never been more proud. And I’ve given birth 4 times," Lively's post continued.

Fans are under the assumption Lively is Lady Deadpool based on the actress's clothing in the post, which matches the same color as the anti-hero's suit.

"It's time! Lady Deadpool," one commenter said, while another jumped in to ask, "Is this a confirmation that you are in it?"

Who is playing Lady Deadpool?

Reynolds nor popular movie website IMDB have confirmed the popular character's casting.

Other actresses who are slated to make cameos in the film are Jennifer Garner, who is reprising her role as the dagger-wielding Elektra, and Dafne Keen, who will reprise her role as X-23, according to IMDB.

Keen was revealed in the film's final trailer, while Garner has not been seen in any trailers or released footage. The 19-year-old actress expressed her excitement to play X-23 again in an Instagram post she shared on Friday.

"Let’s (expletive) gooooo! @deadpoolmovie," the post said.