AJ, 32, has been vacationing in America after he lost his belts to Usyk in September.
The British heavyweight relinquished the WBA, WBO, IBF and IBO world championship belts to the Ukrainian great.
Usyk won the fight via unanimous decision, with the three judges scoring the contest 115-113, 116-112 and 117-112 in his favour.
Joshua is apparently biding his time as to whether he should sack his long-term coach or not.
Joshua was seen laughing and joking with the Mexican as the pair shared a moment together.
Coincidence? Perhaps not.
Joshua attended Alvarez's fight against Rocky Fielding at Madison Square Garden in New York in December 2018 and admitted he was blown away by what he saw on the night.
Alvarez, 30, floored Fielding four times, including twice in the third round, when the fight was stopped.
Speaking to FightHype.com, Joshua said: "I rate Canelo [Alvarez] like from when he fought [Floyd] Mayweather.
"He took a loss, without no reign you don't appreciate the science and appreciate what it's like to lose and bounce back, and he's been improving ever since.
"Watching him live, watching the way he was setting up his body shots and feints, and then watching the crowd, the Mexican crowd, and the New York crowd and stuff, I enjoyed it, I really enjoyed it."News Now - Sport News