The GI Jane actor debuted a line of bathing suits and bikinis in partnership with swimwear brand Andie in July.
Among those to receive swimwear from the line is Willis’s wife, Emma Heming, whom he married in 2009.
Emma shared a photograph of herself wearing the swimsuit in the style “The Marseilles”, which retails for $155 (£130), to her Instagram story, writing in the caption that she was “loving” the collaboration.
Proving that there is no bad blood between the pair, Moore reshared the post to her own Instagram, adding three red heart emojis.
Willis and Moore married in 1987, and share three daughters; Rumer, 34, Scout LaRue, 31, and Tallulah, 28. They announced their separation in 1998 and their divorce was finalised in 2000.
The former couple have maintained an amicable relationship, with Willis telling Rolling Stone at the time of the divorce that they were committed to raising their children together.
“We’re probably as close now as we ever were,” he said. “We realise we have a lifelong commitment to our kids.”
He continued: “Our friendship continues. The institution has been set aside…It’s difficult to live your life and marriage under a magnifying glass, which is what happens to movie star couples.”
Emma and Willis have two children together, daughters Mabel, 10, and Evelyn, eight.
In March, Emma and Moore released a joint statement announcing that Willis had been diagnosed with aphasia, a disorder that impacts a person’s cognitive abilities.
“This is a really challenging time for our family and we are so appreciative of your continued love, compassion and support,” the statement, shared by Emma said.
“We are moving through this as a strong family unit and wanted to bring his fans in because we know how much he means to you, as you do to him. As Bruce always says, “Live it up” and together we plan to do just that.
“Love, Emma, Demi, Rumer, Scout, Tallulah, Mabel, and Evelyn.”