The top two seeds at the Paris Masters enjoyed a training session before the start of the final ATP Masters 1000 event of the season on Sunday.
Alcaraz shared a picture on social media post his practice session with Djokovic and wrote: "I'm in Paris! Great practice with @DjokerNole today! Vamos!"
The top-seeded Djokovic, a six-time champion at Bercy, will open his tournament against doubles partner Miomir Kecmanovic or Argentine Tomas Martin Etcheverry.
Alcaraz, the second seed, will try to make a good start against home favourite Alexandre Muller or Roman Safiullin. He is pursuing his seventh trophy of the season.
Djokovic currently owns a 500-point lead over Alcaraz in the ATP Live Race To Turin, which serves as a barometer for the year-end World No. 1 battle. But with 1,000 points up for grabs in Paris and the ATP Finals still to come, the battle is very much alive.
One year ago, Alcaraz became the youngest year-end World No. 1 in ATP Rankings history. Djokovic is trying to earn the honour for a record-extending eighth time.