Fellow Bachelor franchise alums celebrated Peth's happy news on Twitter, with Chris Bukowski writing, "Congrats buddy!"
Jason Tartick shared a similar sentiment.
Vadher took to her Instagram Story to share messages of love she's received since getting engaged, two of which came from Wells Adams, who appeared on Bachelor in Paradise with Peth, and his fiancée, Sarah Hyland.
"This makes me very happy. Well done @pethderek," Adams wrote. "Welcome to the family @saffron!"
The posts she shared also included a close-up shot of her stunning ring, as well as an additional selfie with her fiancé.
Peth first appeared on JoJo Fletcher's season of The Bachelorettein 2016. He joined Bachelor in Paradise the next year, where he got engaged to Taylor Nolan. The pair called off their engagement in 2018.
Peth continued his Bachelor Nation journey by appearing on BIP in 2019, where he dated Demi Burnett and showed interest in current Bachelorette Tayshia Adams.
Watch the video below for more celebrity engagement news.