Jennifer Lawrence Being 'Incredibly Secret' About Wedding Planning With Fiance Cooke Maroney

A source tells ET the lovebirds are planning a 'casual' ceremony for their family and friends.

Jennifer Lawrence can't wait to walk down the aisle!

A source tells ET that the 28-year-old actress and her fiance, Cooke Maroney, are "head over heels in love," and have been "truly inseparable" ever since the art director got down on one knee.

"[They] recently signed onto an amazing luxury apartment in New York City," the source says. "They have been so busy planning their wedding -- their first choice of locations is New York, but it's not finalized yet. They have been incredibly secretive because privacy is a big priority for them."

"They are both very low key and down to earth and want nothing more than to avoid a 'stuffy, pretentious' atmosphere," the source continues, adding that Lawrence's famous pals, Amy Schumer and Emma Stone, will "definitely" attend the nuptials. "Their vision is traditional with a relaxed and causal ceremony, they mainly just want to share their love with friends and family and to express their happiness to those closest to them."

And even though they have yet to say "I do," it sounds like Lawrence and Maroney are already thinking about expanding their family.

"They both want children and have been discussing starting a family," says the source. "Their families truly believe they are meant to be; his family loves her family and vice versa, so their parents are excited. Their parents get along so well and are all looking forward to big family get-togethers."

ET spoke with Lawrence earlier this month at the premiere of her new movie, X-Men: Dark Phoenix, in Los Angeles, where she revealed how she knew Maroney was "the one."

"Well, he's just the best person I've ever met in my whole life," she gushed. "It was a very, very easy decision."

News broke in February that Maroney had proposed to Lawrence after the actress was spotted rocking a diamond sparkler on her ring finger while out and about in New York City. The pair have been romantically linked since last June.

For more on the couple, watch the video below!

Reporting by Adriane Schwartz.