Colin Hanks wished his dad Tom Hanks Happy Birthday by posting a picture of Michael Keaton.

The 'Sleepless in Seattle' star's son has had a running inside joke with his father in which he shares a picture of the 'Jack Frost' actor to mark his birthday and Tuesday (09.07.19), when he turned 63, was no different.

Colin, 41, captioned the snap of Michael on Instagram: ''Wanna wish a Happy 63rd Birthday to my dad!!! ''He's a good man with a great sense of humor. Love ya Pops! (sic)''

In 2016, he posted a picture of the 'Batman' star in 1982's Night Shift' for Tom's birthday and last year one from 1983's 'Mr. Mom'.

The pair are still yet to let on what the joke is about.

Michael starred alongside Tom in 'Toy Story 3' in 2010 as Woody and Ken respectively.

The 'Inferno' actor celebrated his birthday by jumping fully clothed in his brand new ''beach'' wear off a yacht.

Alongside a video of him dropping feet-first into the crystal blue sea, he tweeted: ''Look at the cool beach clothes I got for my 63rd birthday.''

Meanwhile, Tom recently admitted he was surprised when he found out 'Toy Story 4' was being made.

He said: ''I had no idea where they would take this and in fact, when they said, hey there'll be a fourth. I was like, 'Are you sure? You really wanna take a stab at this?' They no longer give you a script or they show you what the story is - they just talk to you. Maybe perhaps to talk themselves into it aswell. They never really talk about what the point of it is going to be because they find that out along the way.''

However, now Tom insists he ''wouldn't be surprised'' if there ended up being a 'Toy Story 5'.

He said: ''Well, no one is planning on it, but I wouldn't be surprised if somewhere two-and-a-half years from now someone has this kernel of an idea that could become it.

''None of the 'Toy Story' movies are in a schedule, they're not in a pipeline. They don't say, 'on this date, we'll start work on the next 'Toy Story' movie'. They wait until someone comes up with a Toy Story idea that is worthwhile pursuing. But I think it's better that no one is anticipating that; I think there is a strength in saying, 'this is as far as we've been able to go and we don't see anything else coming after that', because otherwise it ends up being some inorganic approach to something that has been very, very organic.''