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As someone who's been married six years, Jack Black knows a thing or two about keeping the spark alive.

When the 42-year-old actor learned his good friend and former costar Angelina Jolie is engaged to Brad Pitt, her partner of seven years, Black offered some sage advice via Entertainment Tonight.

"I think the sex actually improves once you've sealed the deal. It gets better," Black said. "Maybe not for everyone, but for me, once we sealed the deal and we shut off all the exit holes and said, 'No, this is it. We're in it for life,' then we really let loose."

Black -- who accidentally revealed Jolie was expecting twins in 2008 -- also shared some honeymoon planning tips.

"I recommend to Brad and Angie, go to Big Sur for your honeymoon," the Bernie actor said. "Leave the kids with the nannies just for a couple days.

Pitt's three-time costar Julia Roberts also weighed in on his engagement to Jolie, who next stars in Disney's Maleficent. "It's exciting news," Roberts, 44, told E! News. "It's always nice when you're ready to hitch your wagon for eternity to somebody."

The Mirror Mirror actress has already thought of a gift idea for the couple who has everything: "Babysitting!" Roberts said. "Yeah, that's good."