Israel Adesanya, a mixed martial arts (MMA) champion who was born in Nigeria, shared pictures of Mark Zuckerberg's training sessions on social media.
It occurs just before a probable fight between South-African-born Musk, 52 and Zuckerberg, 39.
"We both have South Africans to deal with," Adesanya shared via media.
The 33-year-old Nigerian fighter is due to compete in an Ultimate Fighting Championship (UFC) middleweight match against South African Dricus du Plessis in September.
According to reports, Adesanya arrived at a residence owned by Zuckerberg and located in northern California to begin their training sessions.
The fight's date has not yet been determined.
However, the two are already engaged in another clash due to Meta's recent introduction of a Twitter alternative – Threads.
More than 70 million users have downloaded the Threads app to date.
*Extremist organization banned in Russia