She was Richie Cunningham's sweet little sister, and because "Happy Days" was such a 1970s megahit, that meant she was everyone's little sister.

Erin Moran, who played Joanie Cunningham on "Happy Days" and "Joanie Loves Chachi," was found dead Saturday at age 56, CBS News confirmed. The cause of death was not immediately revealed.

Moran's "Happy Days" family shared memories of the actress online.

Fans of Moran and "Happy Days" also shared their thoughts.

@hwinkler4real No more Mr. C. No more Arnold. No more Al. And now no more Shortcake.

These #HappyDays are sorta sad right now Fonz.

— Vince 22 (@VinceGagliardi) April 23, 2017

@hwinkler4real Woah!! RIP Shortcake pic.twitter.com/vqmsjyx23I

— RON (@YankeeRON_) April 23, 2017

@hwinkler4real Some souls are too fragile for the constant vagaries of this world. May the peace she sought find her, surround and comfort her.

— phair (@phair1) April 23, 2017

@RealRonHoward I was very sad to hear this. I met her a few times when she came into a shop I worked in,she was kind & I really enjoyed our conversations.

— Carrie Jones (@carrie_j1975) April 23, 2017

@RealRonHoward R.I.P. Joanie...love & miss u babes.. pic.twitter.com/SrfN3mKIuJ

— Dee Love Lee (@DeeLoveLee1) April 23, 2017

@RealRonHoward You added the thoughtfulness to the show and Erin added the sparkle. That's how I saw it. Great show many people enjoyed watching together.

— Ellery Woke (@LREwoke) April 23, 2017

If U were an '80s kid it wasn't just Chachi that loved Joannie-Everyone did.Her life after never seemed 2 work out. https://t.co/BEZ4sPeqJz

— Andy Lewis (@andyblewis) April 23, 2017

Happy Days was an after school staple. Basically my babysitter. RIP Erin Moran. https://t.co/ShJwFSFIyq

— Murray Pam (@Pammerhockey) April 23, 2017

The more I think about it, the more I think Happy Days S1 Joanie was the best Joanie. Spunky. Nosy. Smart-ass. Best. pic.twitter.com/5MqiUXMsvB

— Jen Chaney (@chaneyj) April 23, 2017

RIP Erin Moran. My favorite Happy Days episode is when she has a crush on Potsie because relatable. pic.twitter.com/UxsoT6dGv8

— Amelia™ (@sleepyserenade) April 23, 2017

I've known Erin Moran since childhood doing "GunSmoke". More recently as a troubled soul. So saddened to hear of her passing. RIP ERIN xo pic.twitter.com/R3CQyFdlz8

— Willie Aames (@WAames) April 23, 2017

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