Zui Hou Jue Ding Ai Shang Ni

Two strangers, both proposed marriage to their respective girl/boyfriend, were rejected on the same day. They decided that the best way to deal with the rejection was to get drunk, real drunk. During the 24 hours of their crazy drunkenness, these two stranger became fast friends and got married... to each other. When they finally sobered up, they embarked on a mission to undo every crazy thing they did while they were drunk and prayed that their girl/boyfriend don't find out.

(Source: MyDramaList)