Lightbourne rode with Travolta and his son in Jett's last moments.
"It was me, him and Jett," Lightbourne told ABC's "Good Morning America" Jan. 5. "I'll never forget this day. I saw him lean over and hug his son and kiss his son and tell him he loved him and I did everything I could. I saw love in his eyes, I saw love. [Travolta] hugged him, put his arm around him, kissed him on the forehead and the cheek and told him he loved him. He then turned to me and gave me a hug and said, 'You guys did a wonderful job.'"
People magazine reporter Mike Fleeman, who heard the hidden-camera tape, said it represented a "smoking gun" against Lightbourne but may not be allowed in the courtroom as the defense is strongly opposed to its inclusion in the trial.
Both Lightbourne and Bridgewater have pleaded not guilty to conspiracy to commit extortion. If convicted, they could face up to 10 years or more in prison.
ABC News' Mary Rose Abraham and Lee Ferran contributed to this report.