"They have been in prenup talks for a few months," a source revealed.
However, that doesn't mean that the two are having a hard time coming to an agreement that protects their assets and determines who gets what if they were to ever get divorced.
"The process has been extremely effortless," the source said. "These are two mature adults that love each other."
So far, there have been "no hiccups, or outrageous demands" on either side, but the final documents haven't been drawn up yet, the source noted.
Apparently, the 51-year-old feels that a prenup is necessary after she decided not to have one with her ex-husband of 13 years, Bush frontman Gavin Rossdale, whom she married in 2002. The two apparently had a difficult split after rumors of infidelity emerged.
"She just can't afford to not have it with Blake," the source said of getting a prenup, which would protect her if the romance went south.
An anonymous source told People a few days ago that the engagement was a surprise to the No Doubt songstress.
"Gwen is ecstatic. The proposal was a surprise," an insider claimed. "Gwen and Blake kept the proposal quiet for a few days, but were very excited to share."
The two announced their engagement via social media, with an image showing the two kissing inside the chapel at Blake's Oklahoma ranch as Gwen held up her hand to show off her pricey engagement ring.
As The Inquisitr previously reported, Blake is said to have proposed in the chapel because he built it to make her transition from Los Angeles to Oklahoma easier. A source said that while the two had been talking about marriage for a while, the actual event was completely unexpected.
"This engagement was a long time coming but for them it is the right time," they said.
The couple first met in 2014 on the set of The Voice as they were both in the process of splitting from their spouses. Gwen and Blake began dating in 2015 as their previous relationships were officially over, and they've been together since then. According to some insiders, the couple's big day could very well happen before the year is out.