UPDATE 8:45 p.m. ET: Carrie Fisher’s brother, Todd, told Entertainment Tonight that his sister is in the intensive care unit of the hospital where she is “being well looked after.” “If everyone could just pray for her, that would be good,” he told ET. “The doctors are doing their thing and we don’t want to bug them. We are waiting patiently.”

Todd added that Carrie’s condition is unknown. “We don’t know. We hope for the best,” he said. “We certainly do not know her condition — that’s why she is in ICU. I’m sure everyone wants to speculate, but now is not the time for that.”

UPDATE 7:02 p.m. ET: Carrie Fisher’s brother, Todd, told the Associated Press that she’s “out of emergency” and stabilized at the hospital. Her daughter, Billie Lourd, and her beloved dog, Gary, are also by her side, according to TMZ.

UPDATE 5:49 p.m. ET: Paramedics reportedly performed CPR on Carrie Fisher for 15 minutes until they were able to get a pulse, TMZ reports. The actress is currently on a ventilator at UCLA Medical Center.

UPDATE: According to the Los Angeles Times, Fisher is in critical condition at a Los Angeles hospital. A source, who was not authorized to discuss the incident, told the paper that the actress was “in a lot of distress on the flight.” According to TMZ, United Airlines says its crew reported Fisher as “unresponsive” when they landed.

In a statement posted by the Los Angeles Fire Department, the LAFD “responded to LAX International Airport, Gate 74, for a patient on an inbound flight in cardiac arrest. LAFD firefighter paramedics were standing by for the plane’s arrival, provided advanced life support and aggressively treated and transported the patient to a local hospital.”

Original story continues below:

Carrie Fisher suffered a massive heart attack while on a flight from London to LAX on Friday, December 23.

According to TMZ, people on board the flight administered CPR, and once the plane landed in Los Angeles, paramedics rushed Fisher to a nearby hospital.

Actor Brad Gage was on the flight and witnessed the health scare. “I’m in complete shock. @AnnaAkana and I sat in front of Carrie Fisher on our flight from London and she was just taken off the plane by EMTs,” he tweeted Friday afternoon. Actress Anna Akana was also on the flight and tweeted that Fisher “wasn’t breathing for 10 minutes or so” and that “they were administering CPR up until we landed.”

Harrison Ford, who played Han Solo in the original Star Wars films, told The Hollywood Reporter on Saturday, December 24: “I’m shocked and saddened to hear the news about my dear friend. Our thoughts are with Carrie, her family and friends.”

Actor Peter Mayhew, who plays Chewbacca, also sent his thoughts and prayers to his Star Wars costar.

Thoughts and prayers for our friend and everyone’s favorite princess right now.. @carrieffisher — Peter Mayhew (@TheWookieeRoars) December 23, 2016

Star Trek star William Shatner asked followers to pray for Fisher.

I ask everyone to stop for a moment and send special thoughts to @carrieffisher. — William Shatner (@WilliamShatner) December 23, 2016

Other celebrities took to social media to send well wishes to Fisher, including Star Wars’ Luke Skywalker himself, Mark Hamill, The Force Awakens actress Gwendoline Christie, actor Michael Rosenbaum, Fifty Shades of Grey author E.L. James, songwriter Diane Warren and director Kevin Smith.

I’m devastated. Everyone send their prayers to my good friend @carrieffisher – I know she’ll pull through. @LourdBillie @DaveMirkin — Michael Rosenbaum (@mrosenbaum711) December 23, 2016

The world waits. Sending love and light to @carrieffisher and her family. — E L James (@E_L_James) December 23, 2016

Carrie Fisher please b ok!!! — Diane Warren (@Diane_Warren) December 23, 2016

@carrieffisher The whole world is sending you so much love! Sending you the universes most powerful Force XXXXX❤❤❤ — Gwendoline Christie (@lovegwendoline) December 23, 2016

as if 2016 couldn’t get any worse… sending all our love to @carrieffisher — Mark Hamill (@HamillHimself) December 23, 2016

Much much much much much much love going out to Carrie Fisher right now. Please please please be well. — Jon Cryer (@MrJonCryer) December 23, 2016

I don’t pray much anymore but I am praying for you right now, @carrieffisher. Please pull through… https://t.co/Wq6wrlmrnE — KevinSmith (@ThatKevinSmith) December 23, 2016

My thoughts and prayers R with @carrieffisher RIGHT NOW! I pray God brings her back safely! She’s a sweet woman, back doin what she loves!?? — Corey Feldman (@Corey_Feldman) December 23, 2016

The Star Wars actress was recently on a book tour in London for her latest memoir, The Princess Diarist.

The actress, best known for her role as Princess Leia in the original Star Wars trilogy, most recently appeared in The Force Awakens.

Updates to come.