Khan, 65, arrived in parliament wearing a traditional white shalwar kameez to attend the maiden session of the National Assembly.
He first got himself registered at the parliament. He then asked for a waistcoat to pose for a registration card picture, Urdu langauge daily Jang reported.
One of the NA employees took off his black waistcoat and gave it to Khan. The employee also helped Khan wear the waistcoat, the paper said.
The Pakistan Tehreek-e-Insaf chief then sat on a stool for himself to be clicked.
Khan attended the first session of the 15th National Assembly and took oath of Member of the National Assembly from outgoing speaker Ayaz Sadiq.
He was among the 329 newly-elected members of the National Assembly who took the oath, setting the stage for the cricketer-turned-politician to form the next government, only the second democratic transition of power in Pakistan.
Khan also shook hands and posed for a photo with Pakistan Peoples Party chief Bilawal Bhutto Zardari, who is entering the National Assembly for his maiden term.