Korean versions of AOA's previous Japanese singles, "Give Me the Love" and "Oh Boy", are also included as tracks 8 and 9 respectively.

On December 23, AOA member, Kim Seol-hyun, posted two teasers on her Instagram account with hashtag #AngelsKnock and #20170102.

The first one is of her wearing a white blouse with minimalist makeup and wavy hair; she's also staring at the camera innocently.

The second teaser is of her wearing black blazer, hair slicked back and she's fiercely challenging the camera.

[7] On December 30, a highlight medley was released to preview all of 10 tracks featured in Angel's Knock.

"Excuse Me" shows some cute and feminine choreography with the members putting their hands up as they dance.

[9] On January 1, 2017, FNC Entertainment posted various motion posters featuring all of the members from the singles' music videos on social networks.

Prior to the official album release, AOA hosted a one-hour comeback countdown show titled Angel's Match on Naver's V – Live Broadcasting platform on January 1, 2017 at 11 p.m.

On January 11, FNC Entertainment announced details for the group's first solo concert in the native country Korea, titled "2017 AOA 1st Concert [Ace of Angels] in Seoul", which will be held on March 11 at Olympic Hall, Olympic Park.

"Excuse Me" is a retro-style dance track with an intense drum beat and bass, and a unique synth sound, which is composed and produced by Brave Brothers who previously produced the group's biggest hits including "Miniskirt", "Like a Cat", and "Heart Attack".

On February 10, the group's released a music video for the album track "With Elvis" as a special gift for their fans.