no, Wonbin and Shin Mina just shoot a CF for Maxim T.O.P. brand coffee together

see here

Actors Won Bin (Mother) and Shin Mina (The Naked Kitchen) pair up — and pucker up — for their first kiss in a CF for Maxim T.O.P. brand coffee.

A brand representative explains the target demographic to be 20- and 30-something men and women, and in that spirit, they picked a pretty appropriate couple. I mean, do they make a gorgeous duo or what? (Watch a behind-the-scenes clip of the CF shoot below.)

The ad will begin airing on the major broadcast stations and cable TV on June 1.

Shin Mina’s latest project was singing with rock band Loveholics for “Miracle Blue” as well as promoting her film with Gong Hyo-jin, Sisters on the Road. Meanwhile, Won Bin’s Mother had a fantastic opening day and opening weekend, drawing in more than 1 million viewers to come in #1 in the box office over this weekend.

you can find more pics, videos here, here, and here

Really, i don't think so, never heard Wonbin and Shin Mina have any gossip