A source tells ET, "Jennifer and Alex plan to get married in the summer, and can’t wait for the big day. Jennifer and Alex already do everything together and are basically married, but are excited to make it official."
The source adds that the guest list will include some of the pair's famous exes.
"The couple is all love, and will be inviting their exes," the source notes.
Lopez shares twins Max and Emme, 11, with her ex-husband, Marc Anthony, whom she married in 2004 and finalized her divorce from in 2014. Rodriguez was married to Cynthia Scurtis from 2002 to 2008 and the exes share daughters Natasha, 15, and Ella, 11.
As for the actual nuptials, the A-list couple doesn't plan to have an extravagant day.
"The wedding will be gorgeous, but not huge," the source continues. "The couple wants it to be a fun celebration of love with their closest family and friends. Both of their children will play a big part in the wedding."
ET spoke with A-Rod's daughters following their future stepmother and stepsister's Super Bowl halftime show. Watch the clip below to see their reactions to their performance: