Justin Bieber wrote a tribute to a friend who perished in the recent Paris terrorist attacks.

The 21-year-old "What Do You Mean?" singer's friend, Thomas Ayad, who worked for Bieber's international record label, Universal Music France, was killed in the unfortunate event on Friday, according to Vulture.

Bieber shared a heartfelt message on Twitter, mourning the loss of his friend and expressing his grief over the situation. He also thanked Ayad for all that he had done for him throughout the years.

"RIP Thomas #PrayForParis. Still thinking about Paris and my friend Thomas that we lost in the tragedy. He was a part of the team for years and I wish I would've had more time to thank him. Make sure to appreciate people while you have them. Thanks Thomas for everything you did for me. You are appreciated and missed. Thoughts and prayers are with your family & friends #PrayForParis," Bieber's emotional post read.

Ayad, who also worked at Mercury Records as a product manager, was one of the 89 people killed during the mass shooting at the Eagles of Death Metal concert at the Bataclan Theater in Paris.

Bieber released his fourth studio album, "Purpose," on that same day. The album has produced the singles "What Do You Mean?" and "Sorry." It is the follow-up to his 2012 album "Believe."

Bieber also recently announced plans to head out on his Purpose World Tour starting March 9, 2016. The world tour will include 58 dates, with stops in several U.S. cities, such as Denver, Las Vegas, Dallas, Atlanta, Minneapolis, Boston and Miami. He will also touch down in areas of eastern and western Canada. There will be two-night runs in Brooklyn, Los Angeles, Chicago and Toronto. The tour will wrap up with a show at Madison Square Garden on July 18.