Entertainment Tonight ET Online ETOnline.com

Ray J remains hospitalized in Las Vegas after becoming ill after Sunday's Billboard Music Awards and a rep for the singer says he is currently being treated for "exhaustion and jet lag."

The rep tells ET that Ray J -- one of the few people to spend time with Whitney Houston in her last days -- was taken to the hospital early Monday morning and is still being treated at the Las Vegas facility. 

RELATED: Ray J Denies Any Involvement in Whitney's Death

"Ray J was in Las Vegas hosting a launch party for the product he is endorsing Prince Reigns Hair Serum and to attend the Billboard Awards," said a statement from the rep. "He had just returned to the U.S. from a quick 32 hour round trip from China where he performed a concert and had meetings regarding a new business. Upon landing, he immediately drove four hours to Las Vegas for the two events."

The 31-year-old singer/songwriter's hospitalization comes after a reported clash with Whitney's sister-in-law Pat Houston at the Billboard Awards. Pat  reportedly called security on Ray J when she learned that he was seated next to Whitney's daughter Bobbi Kristina.

RELATED: Ray J Overcome By 'Emptiness' From Whitney's Loss