Chelsea signed Kai Havertz for around £70m from Bayer Leverkusen two years ago.
Havertz is a forward player, who was known for being an attacking midfielder before joining Chelsea.
At Chelsea, Havertz has featured mostly as a false nine under Thomas Tuchel, and it was his goal that won Chelsea the Champions League in 2009.
Usually, players in his position tend to wear the prestigious No.9, 10 or 11 jerseys.
In a Twitter Q&A session, the German international revealed why he chose the number 29.
“Me and my brother used to use the number 29 when we created ourself on FIFA05,” Havertz revealed.
Meanwhile, former Everton striker Jermaine Beckford has claimed that Chelsea boss Thomas Tuchel is not properly making use of Kai Havertz.
“With Kai Havertz, I’m a huge admirer of his. I don’t think he’s built to be a number nine. That’s not his natural position,” Beckford told talkSPORT.
“That’s not where we see the best of him. He works better when he’s working alongside somebody or as a number 10.”
Thomas Tuchel is set to revamp his attack this summer. The Blues have been linked with a number of attacking players.
The likes of Raheem Sterling, Raphinha and Ousmane Dembele have all been linked with a move to Chelsea, with Sterling seeming the most likely deal to happen.