IU appeared on the July 23 broadcast of tvN's 'House on Wheels' to keep her promise with Yeo Jin Goo, the co-star of 'Hotel Del Luna'. In this episode, the members went on a trip to Munkyeong as they enjoyed a relaxing time in an RV (house on wheels).

Throughout the episode, IU and Yeo Jin Goo shared cute, lovey-dovey moments with each other. While preparing for their lunch, IU stood outside the window as she watched Yeo Jin Goo skillfully minced the garlic and the onions. She fondly looked at him cut the ingredients and complimented him stating "I guess you weren't lying when you said you know how to cook."

Then, IU took out the gift she had brought for Sung Dong Il, Kim Hee Won, and Yeo Jin Goo. She took out the coffee that her dad had roasted himself to give to the members. 

Yeo Jin Goo made the hearts of viewers flutter when he had remembered that IU doesn't drink coffee. Sung Dong Il couldn't stop complimenting IU's father's coffee when took a taste of the coffee. Sung Dong Il and Yeo Jin Goo said "it's the best coffee" and IU responded by saying, "My family isn't too informed about coffee so we're not able to react or compliment my dad properly."

This is when Sung Dong Il, an avid coffee drinker, commented "I want to be part of that family." Then all of a sudden Yeo Jin Goo said, "I will try (to become IU's family)."

Perplexed, Kim Hee Won stated, "Are you trying to get married today?"  while Sung Dong Il added, "He keeps making grand statements every time we have a guest." making netizens laugh.

You can watch the compilation of IU and Yeo Jin Goo's lovey-dovey moments below: