The New Kids On The Block singer, who starred with the 30 year-old actress in the 2004 comedy, 'Tony N' Tina's Wedding,' is thrilled she is expecting her first child with her fiancé, Ashton Kutcher, later this year and has no doubt she will adapt to motherhood easily.
The 41-year-old star exclusively told BANG Showbiz: ''She's as sweet as she seems. What you see is what you get with Mila and she's always been really nice.''
He added: ''It's actually been 10 years (since we worked together). I might bump into her and it's been a couple of years since I've seen her but she's really sweet, so I'm sure she's going to be a great mom.''
The heartthrob is currently gearing up kick off the group's upcoming European tour, 'An Intimate Evening with New Kids on The Block' next month and recently announced new dates in the UK and Ireland.
And the 'Summertime' hitmaker, who has three children of his own, Griffin, six, Rhys, four, and Kira, two, with wife Barrett Williams, admits it would be difficult to be away from his family if he didn't still love performing.
He explained: ''Obviously they're number one but my kids love to sing and dance. My oldest son is six and he's come up on the stage with the New Kids. They're like the best uncles to him. He's already a better dancer than I'll ever be and I guarantee he'll be a better singer - so it's in the blood.
''When you have three kids, you want to spend your time the best you can and you want to work hard so you're not wasting your time when you could be with your family.''
And he insists he and his bandmates, Jordan and Jonathan Knight, newly engaged Donnie Wahlberg, and Danny Wood, all still enjoy spending time together.
He said: ''It's really a blessing we've able to stay together this long and get back together because we have more time to be friends. We really do get along and have a great time together; we all play an important part in the group.''
Tickets to 'An Intimate Evening with New Kids on The Block' are on sale now from www.gigsandtours.com and www.ticketmaster.co.uk.