Queen Sirikit of Thailand is reported to have been admitted to hospital in Bangkok for a "detailed checkup".
Television reports said Queen Sirikit, 78, was admitted to Bangkok's Chulalongkorn Hospital late on Thursday and was visited by the king on Friday.
King Bhumibol Adulyadej, 82, has himself been in hospital for more than a year.
He was admitted on 19 September due to fatigue and lung inflammation.
The royal household has not issued a statement. The health of the monarchy is regarded as a sensitive issue in Thailand.