John Travolta paid homage to his late wife, Kelly Preston, Friday, with the help of their daughter.

John and 20-year-old Ella hit the dance floor … something John says was Kelly’s favorite thing … dancing with him.

As we reported, Kelly died last month after a 2-year, very private battle with breast cancer. She was only 57 when she passed away. She and John were married for nearly 29 years.

John posted, “My daughter @ella.travolta and I dancing in memory of momma. One of Kelly’s favorite things, dancing with me.”

John and Kelly had 3 kids together … Jett, Ella Blue and Benjamin. Jett died tragically in 2009, after suffering a seizure.

Watching the video is both sweet and sad.