Lovelyz released "Beautiful Days" long version MV teaser. 

"Beautiful Days" is the title track of Lovelyz' 6th mini album 'Once Upon A Time.' The album also includes 4 other songs titled "Once Upon A Time," "Close To You," "Sweet Luv," and "Secret Story."

The MV teaser takes on a dreamy, spring concept with a soft melody and strong beats of "Beautiful Days" in the background. Watch the long version MV teaser below.

The full release is coming on May 20.