"Nicole has checked into Cedars-Sinai where she is being treated for pneumonia," a rep for Nicole said in a statement to the online outlets. "She is doing well."
Over the weekend, Nicole, 28, posted a message on her Twitter page noting that she was feeling under the weather.
"ok cold, it's been 6 days. Lets part ways graciously & keep it moving," she wrote.
Earlier this week, Nicole was in a Los Angeles courtroom where a judge granted her and longtime beau Joel Madden a temporary restraining order barring two celebrity photographers from coming close to her or her children.
Nicole gave birth to son Sparrow James Midnight Madden in September. She and Joel also have a daughter, Harlow, who turns 2 in January.
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