The X-Men star admits he jumped at the chance to join Flockhart and his acting hero Ford when she asked him to accompany her on a dinner date with the Star Wars icon - and now, looking back, he realises he was a big part of the couple's courtship.
Marsden tells Playboy magazine, "She said, 'Come to dinner with me and Harrison'. I'm like, 'Me, you and him?'
"It turned out to be a small group of us, thankfully, but I ended up as her wingman. We had dinner someplace in Brentwood (Los Angeles) and then went back to his house. He put music on and made everybody drinks.
"He was giggly and goofy around her but pretty aloof with the rest of us. I kept thinking, 'We should leave the two of them alone,' but Calista was like, 'Don't leave, don't leave...'
"I'm making him sound like a rapist, but he was very hospitable. She was just really nervous.
"Anyway, we had more drinks, he played more music and then at some point he gave me a look that said, 'Ok, you've got to get the f**k out of here'."