Juice Wrld, real name Jarad A Higgins, is said to have fallen ill after landing into Chicago from California early Sunday morning.
He was walking through the airport when sources tell TMZ he suffered the seizure.
The rapper turned 21 only last week. On December 3 he tweeted his girlfriend Ally Lotti to say: 'It’s us forever bb girl.' He had earlier said he had had 'one of the best birthdays ever.'
In October of this year rock band Yellowcard announced they were suing Juice WRLD for $15 million for copyright infringement.
They claimed he copied melodic elements of their 2006 song Holly Wood Died for his breakthrough 2018 single Lucid Dreams.
Lucid Dreams is actually structured prominently around a sample of Sting's 1993 song Shape Of My Heart.