The star took to Twitter on Tuesday (May 26) in response to a tweet from the 1995 movie's director Brad Silberling, in which he gave a shout-out the cast, including Ricci and Bill Pullman.
Sawa, who played ghost Casper when he comes to life as a boy in the spooky comedy, joined in on the exchange, revealing his four-year-old daughter was just about to watch the film for the first time and also noted that it was Ricci who helped him land the role.
"Christina Ricci is a HUGE talent and played a big part in me getting the role and then went on to recommend me for (1995 film) 'Now and Then'," he wrote. "I owe her the world."
He also noted that while he played the human version of the supernatural character, it was Malachi Pearson who voiced the ghost throughout the film.
"I was in Casper for 30 secs (seconds). Malachi Pearson did the hard work," he added. "When they decided last minute to bring Casper to life he was too young. So I landed the role. And I'm very fortunate @BSilberling chose me cause I'd be lying if I said it didn't start a 30 year job that I love."