Novak and Andre were spotted together Friday in Beverly Hills in casual digs with their hands full. What's interesting though is what Agassi's carrying -- a Square Panda Phonics and reading game for kids.

Djokovic and his wife, Jelena, just had their second child -- a baby girl -- in September ... so it's gotta be for her right?

As for the coaching ... the Djoker hired Agassi in May to help him repair his form and worked with him for 2 months before an elbow injury knocked him out of Wimbledon. He's reportedly planning for a comeback in January at the Australian Open.

The 2 tennis greats together begs the question -- if you run into them on the street and only have time for one autograph ... who do you ask?