EXCLUSIVE: Carrie Fisher In Intensive Care Unit After Heart Attack, Brother Says: 'We Hope For the Best'

Carrie Fisher's brother, Todd Fisher, gives ET an update on her condition.

Carrie Fisher is currently in the Intensive Care Unit of a Los Angeles hospital after suffering a heart attack aboard an airplane on Friday, her brother, Todd Fisher, tells ET exclusively.

"She is in the intensive care unit, she is being well looked after," Todd says. "If everyone could just pray for her that would be good. The doctors are doing their thing and we don't want to bug them. We are waiting by patiently."

Todd says Fisher's condition is still unknown.

"We don't know. We hope for the best," Todd says. "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."

WATCH: Carrie Fisher Suffers Major Heart Attack on a Plane

Fisher was on a flight from London to Los Angeles International Airport when she went into cardiac arrest. Fellow passengers, including a nurse, then assisted her, according to air traffic control. A source close to Fisher tells ET that as the plane was descending into LAX, Carrie was awakened and "she started throwing up and saying she couldn't breathe."

"They rushed her to the hospital and they are monitoring her heart right now," the source adds.

WATCH: Carrie Fisher Feels 'Really Bad' About Dishing on Her Alleged Romance With Harrison Ford -- 'He's Incredibly Private'

In a statement to ET, Los Angeles Fire Department spokesman Erik Scott said they responded to LAX for a patient on an inbound flight in cardiac arrest at 12:11 p.m. 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.

Fisher's sister Joely tweeted about the news on Friday, writing, "Use the force babe."

-- Additional reporting by Tracie De La Rosa