The two stars had planned for weeks on meeting up for a meal when the Lakers were in Boston, sources told ESPN.com.
While there are no active talks between the two franchises involving a trade for Rondo, sources said the teams did have a brief discussion a few months ago.
It's not clear which team initiated the call.
Rondo will be a free agent this summer, and sources stressed that the Celtics would prefer to re-sign him.
Their willingness to engage in talks regarding Rondo is merely informational at this point, sources said.
However, the Lakers have long held interest in the point guard, who helped Boston defeat them in the 2008 NBA Finals, and sources indicate he is high on their list of free-agent targets this summer.
Should the teams re-engage in discussions about Rondo, sources indicated Boston likely would ask for at least one first-round draft pick.
The Lakers owe their own first-round pick to the Phoenix Suns unless it falls within the top five picks. They also own Houston's first-round pick.
The Lakers could include Steve Nash, who has been ruled out for the season with a back injury. Nash is making $9.7 million this season, the final year of a three-year contract with the Lakers.
However, league sources indicate the Lakers have thus far been reluctant to engage in discussions including their first-round draft picks after working so hard this past offseason to acquire a pick this season.
Rondo's injury history makes it even less likely they'd part with one of their picks for a player they could simply sign as a free agent this summer.
Bryant often has expressed a fondness for Rondo and his style of play. Back in 2013, Bryant told ESPNBoston.com: "You don't want Rondo? Send him my way. I love everything about him. Everything. I love his attitude, I love his chippiness, his edge, his intellect, his know-it-allness. All of it. That's what makes championship players.
"What guard have you seen at his size that will get you 18 assists, 17 boards and 20 points all in one game? That's unheard of. I love that kid. I always make a point of talking to him during All-Star [Weekend]. He's one of my favorites."
Bryant later complimented Rondo by saying, "From what I understand, he's an a--h---, like me."
Rondo responded by noting, "That's a great compliment, coming from Kobe. I feel the same way about him."
The Celtics and Lakers meet Friday night at TD Garden.
ESPNBoston.com's Chris Forberg contributed to this report.