Though they officially signed their divorce papers in July, Khloé Kardashian has been open about how much she still cares about ex-husband Lamar Odom, who was hospitalized in Las Vegas on Tuesday.
Sources tell PEOPLE Kardashian has been informed of Odom's condition – which is described as serious – and is flying to be by his side Tuesday night.
Just two weeks ago, on an episode of Keeping Up With the Kardashians, Khloé expressed how she's "always going to be there for" Odom, 35, and that she was worried about the former basketball player after his best friend Jamie Sangouthai died in June.
"This is all just really upsetting," Kardashian said in an interview after Odom had reached out to the reality star following the tragic news. "He's distraught and devastated. Lamar has suffered so much loss in his life. I'm always going to be there for Lamar, especially when something as tragic as this happens."
She added: "I'm really on high alert for Lamar because I mean, anything I think will set him to spiral, and that's kind of the last thing I want for him."
Khloé, 31, has previously expressed her desire to check in with her ex-husband.
"Lamar and I loved each other deeply, and I don't believe in just acting like that relationship never existed," Kardashian said in an interview on an episode of KUWTK last month. "Things happened, but that doesn't just stop me from caring about him or loving him."
In August, the former couple got into an altercation and at the time, a source told PEOPLE that Kardashian was "worried" about Odom.
"Khloé is still very upset about the incident," a source close to Kardashian told PEOPLE. "But she's also worried about Lamar. He is clearly not well."
In July, the KUWTK star opened up about her relationship with Odom in an interview with Complex magazine.
"Lamar is genuinely one of the best people I've ever met, and everyone says that when they meet him," Kardashian told the magazine. "I think Lamar's going to always be that person [for me] but that's what made it so special."
Kardashian and Odom wed in 2009 just one month after meeting. But after Odom relapsed with his substance abuse problems and cheated on Kardashian, she filed for divorce in December 2013.