The Hollywood couple has been plagued by gossip suggesting their six-year union is in trouble ever since they spent their wedding anniversary apart on September 24th.
There has also been speculation about Kutcher's infidelity, but neither star has spoken out about the alleged scandal.
However, actions spoke louder than words on Friday when the pair put on a united front as Moore stopped by Kutcher's Hollywood back-lot set to show her support.
A source tells UsMagazine.com, "Demi didn't come on the actual shooting set or anything - she never does - but she spent the day on the lot in his massive trailer... He put his arm around Demi and they acted like a couple. They were talking and smiling at each other. Everything seemed just like normal."
Moore was joined on set by her 23-year-old daughter Rumer.