Megastar Amitabh Bachchan, who recently signed a poster of his film "Don" for Shah Rukh Khan, says posters of old movies have become rare and that he appreciates those who collect them.

The 70-year-old recently did a photo shoot for Filmfare magazine with thespian actor Dilip Kumar and superstar Shah Rukh Khan to commemorate 100 years of Indian cinema.

He also signed an original poster of his 1978 blockbuster "Don" for Shah Rukh.

"After the photo shoot with Yusuf Saheb (Dilip Kumar), and Shah Rukh is over, Shah Rukh asks me to sign the original poster of 'Don'. I think the posters of old (films) are becoming very rare," Big B posted on his blog.

"There are some still most favoured people that collect these memorabilia, and I am happy that they do. Posterity must know what the past was all about. Present without a past is incomplete," he added.