Dakota Johnson's signature front teeth gap may be 50 shades freed, but that doesn't mean the actress is happy about it.

Johnson appeared as a guest on The Tonight Show Starring Jimmy Fallon on Tuesday (August 6), where she divulged the reason for her noticeably new smile — and that reason may surprise you!

The actress first noted that she finds it hilarious that the state of her teeth is headline-worthy news: "First of all, the fact that this is a newsworthy event in our world right now is pretty shock-a-khan to me."

She also revealed that she didn't close the gap in her front teeth on purpose or cosmetically, but shared that it "closed by itself" naturally following a recent procedure.

"I had a permanent retainer since I was like 13, and it was just glued to the back of my teeth," she explained. "I was having a lot of neck problems recently, so my orthodontist, she decided that it would be a good idea to take it off and see if my jaw expanded and it helped me. My gap closed by itself."

Johnson quipped that she's "sad about it, too," joking that she'd "really appreciate some privacy during this time. I have to deal with a whole new world of problems, getting food stuck in my tooth because before it would slide right through."

But hope is not all lost for her beloved tooth gap, she added. "It’s gonna come back — other retainers, the world of dentistry is so advanced," she hinted.

Watch her interview with Fallon, below:

Celebrities' Plastic Surgery: See Before and After Photos