Michael Urie says Harrison Ford's "cantankerous" persona is "just an act".

The 45-year-old actor has got to know the Hollywood legend on the set of comedy drama Shrinking, and he insisted the 83-year-old star is actually quite "silly" on set, despite a somewhat grumpy reputation.

He told PEOPLE magazine: "He's silly and makes work fun. He loves being [on set], he really, really loves being there.

"I know he seems cantankerous on the red carpet, [but] that's just an act. He's actually very sweet, and he loves being there."

Michael has also heaped praise on Harrison's commitment to his craft, and the care he puts into every scene.

He added: "He is a really careful actor, he's really thinking about the work. He really cares about the scene; he treats every scene like it's its own thing."

Meanwhile, earlier this year Harrison opened up on how he has achieved a long lasting love with his wife Calista Flockhart.

The Indiana Jones star has been married to the 60-year-old actress since 2010 and he's insisted he still enjoying the delights of being in love now he's in his 80s.

During an appearance on NPR's Wild Card with Rachel Martin, he explained: "Old people can love, too. You know, you think about falling in love and all of that business.

"You think it's the business of youth or something, you know, and staying in love is the issue."

Harrison went on to add the secret to his healthy marriage is "maintaining, nurturing, basically, not f****** up."

The actor was previously married to Mary Marquardt between 1964 and 1979) and then to Melissa Mathison from 1983 until 2004 and he insists he'll always regret walking down the aisle when he was in his early 20s.

When asked how long he has been married to his third wife, he joked: "If you ask me, I would say all my life. I was married for the first time at 23 years of age, which should be illegal."