In an Instagram story posted Monday, the actor, 27, said that he and Spears, 39, would be protecting their personal assets before tying the knot.
"Thank you to everyone who is concerned about the prenup. Of course, we're getting an ironclad prenup to protect my Jeep and shoe collection in case she dumps me one day," he joked along with two crying-laughing emojis.
While Asghari didn't mention any concerned fans specifically, Oscar-winning actress Octavia Spencer urged Spears to get a prenup on Instagram, where she commented on the singer's post announcing her exciting engagement news.
Sam Asghari Instagram Britney Spears and Sam Asghari
"Make him sign a prenup," Spencer wrote, as captured by Instagram account Comments By Celebs.
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Spears — who has been in an ongoing legal battle with her father Jamie Spears over her conservatorship — revealed the engagement on Sunday, sharing the news with a joyful Instagram post. The "Gimme More" singer posted video of herself flashing her new diamond ring as she stood beside Asghari, writing in the caption, "I can't f—ing believe it 💍💍💍💍💍💍❣️!!!!!!"
Vivien Killilea/Getty Britney Spears and boyfriend Sam Asghari
Spears and Asghari have been dating for more than four years. The couple first met on the set of Spears' "Slumber Party" music video in 2016. In an earlier Instagram Story posted Monday following the news, Asghari wrote, "My phone exploded today! Thank you for the overwhelming love and congratulations! We both love every single one of you."
Asghari's manager, Brandon Cohen, told PEOPLE in a statement Sunday he was "proud to celebrate and confirm the engagement," adding, "The couple made their long-standing relationship official today and are deeply touched by the support, dedication and love expressed to them."
Sam Asghari/Instagram Sam Asghari
Asghari and Spears' engagement comes not long after a source told PEOPLE in June that the pair was ready for a future together.
"He's ready for marriage and kids with Britney and is serious about the relationship. She wants to take that next step and have that full life with him," the source said. "As a couple they've hidden how they've really felt even from people close to them because they were anxious and scared, but now it's all out there."
Spears previously thanked Asghari for helping her get through the "hardest years of my life," in an August Instagram post. Now, the pop star is thrilled that she's headed down the aisle with Asghari.
"Britney is ecstatic," a source told PEOPLE Sunday.