Naomi was cheering from the crowd as she watched her former partner is his latest Broadway play, Les Liaisons Dangereuses.
The 48-year-old stepped out in New York City's Booth Theater, flashing her signature grin for cameras, before watching Liev.
Chatting to Entertainment Tonight, Naomi explained why she felt the need to the play.
Check out more from Naomi's chat in the video player... Article continues below!
"He's the father of my kids," she admitted to ET, speaking of their two sons, nine-year-old Alexander Pete, and seven-year-old Samuel Kai.
"So it was important to support him."
And Naomi, who had been with Liev for 11 years before they announced their split in September, wanted to see her former flame in action.
"I was very curious to see this and all of his work," she gushed.
"The play is fantastic and really I hope everyone gets to see it because he does some extraordinary work up there."
In September the pair, who met in 2005, released a joint statement in September confirming they were ending their relationship.
"Over the past few months we've come to the conclusion that the best way forward for us as a family is to separate as a couple," they said at the time.
"It is with great love, respect, and friendship in our hearts that we look forward to raising our children together and exploring this new phase of our relationship."