The duo ran into each other outside the practice courts at the All England Lawn Tennis Club.
Williams, who received a wildcard for this year’s Grand Slam, was warming up for her first-round match against Harmony Tan of France.
As she left the practice court, she bumped into Nadal, who was preparing for his opening encounter against Argentina’s Francisco Cerundolo.
As the pair crossed paths they embraced, with Nadal asking Williams how she was.
The 23-time Grand Slam winner replied: ““Hey, how are you? Congratulations on everything”.
Williams stunned the world when she announced she would be returning to the tennis court this month.
The 40-year-old made her comeback at the Eastbourne International last week, playing in the doubles tournament with Ons Jabeur.
Rafael Nadal and Serena Williams stopped to say hi as Serena left her practice court and Rafa went to his.— Yasmin Syed (@yasminstefsyed) June 27, 2022
He asked how she’s doing and she said congrats for everything. #Wimbledon pic.twitter.com/znIuldJuzz
It was the first time she had appeared on the WTA Tour for nearly 12 months, having suffered a leg injury at Wimbledon last year.
Williams will begin this year’s campaign against Tan on Centre Court this afternoon. She is seeking her eighth Wimbledon title and a record-equalling 24th Grand Slam title.
Nadal has also been plagued by injury this season. He suffers from Muller-Weiss syndrome, a rare condition which causes chronic pain in his left foot.
He is on the hunt for a third Wimbledon title, although grass is certainly not his favoured surface.
Wimbledon got underway yesterday, with Emma Raducanu, Ons Jabeur, Anett Kontaveit and Angelique Kerber among the first round winners.
Maria Sakkari, Coco Gauff, Iga Świątek and Karolína Plíšková are among the stars set to be in action today.
It remains to be seen whether Świątek can maintain her impressive 35-match winning streak, which includes six successive WTA titles.
Grass is not the 21-year-old’s favoured surface, and Wimbledon will be her first grass-court tournament of the season.
But Świątek is still considered the favourite to win the Grand Slam due to her dominant form.