Lee Jong-suk won the grand prize at the 2022 MBC Drama Awards on December 30th.
In his acceptance speech, he thanked someone without naming them.
Korean media outlet Dispatch published a report and photos on December 31st claiming to show Lee Jong-suk and IU on a dating trip in Japan.
The report suggests that Lee Jong-suk and IU have been in a "relationship" since 2012, when they first met on a TV music show.
The report also claims that Lee Jong-suk and IU spent several days together at a luxury resort in Nagoya, Japan.
A person close to the two said that their relationship has already been acknowledged by their families.
IU sang a congratulatory song at Lee Jong-suk's younger sister's wedding.
Lee Jong-suk invited IU's younger brother to join him on a trip to Japan for Christmas.
Lee Jong-suk and IU flew out of Korea separately, stayed together in Japan, and then returned separately
Lee Jong-suk and IU have been referring to each other in their respective public statements.