Tom Hanks thinks he's a ''cool'' grandparent.

The 60-year-old actor - who has four children, Colin, 39 and Elizabeth, 34, with his late ex-wife Samantha Lewes, and Chet, 29, and Truman, 21, with his wife Rita Wilson - is grandfather to three children, and says the little ones keep him ''entertained'' when he is watching them.

He told 'Entertainment Tonight': ''When you have grandkids, if you're with one of them - or all three of them - look, there's no book, no radio, no TV. You're going to be entertained by them every moment that you're there. Sit back and watch the show!''

Both the 'Sully' star and his spouse, also 60, believe they are fun grandparents to six-year-old Olivia and three-year-old Charlotte, whose father is Colin, as well as Chet's unnamed baby daughter.

Rita said: ''We're the cool grandparents.''

To which Tom added: ''I think [we're] the most cool.''

Meanwhile, the 'Forest Gump' actor recently admitted his marriage to Rita doesn't take ''vast work'', and although people think it is hard to maintain a relationship in the public eye, Tom doesn't think it is much different as he and his wife complement one another very well.

He said: ''People say, 'Jeez, it must be hard to stay married in show business.

''I think it's hard to stay married anywhere, but if you marry the right person, it might work out. We give each other a natural sense of support for whatever the other wants to pursue.

''Our marriage doesn't require vast work. We have been married 28 years and dig each other a lot.''