Jenelle Evans is officially engaged to her on-again, off-again boyfriend Gary Head.

"I'm the luckiest girl in the world to have Gary Head in my life," the Teen Mom 2 star tweeted on Wednesday along with a photo of her engagement ring.

"The ring is a princess cut solitaire diamond," a source told Us Weekly, adding that Evans is completely smitten with her new fiance. "She's in love with him entirely."

Evans finally accepted Head's proposal after expressing some initial hesitation to commit, Us reported.

"Gary asked her to marry him last month. She wasn't certain about Gary and didn't want things to be that serious between them," the source said.

Evans, 20, and Head, 22, have apparently been dating for five months with a couple breaks in between.

"I'm very depressed. Me and Gary broke up for good," the reality TV star tweeted on April 8.

Shortly after she and Head temporarily ended their relationship, Evans reportedly reconciled with former boyfriend Kieffer Delp -- but it didn't take long for the couple to split again, as they called it quits at the end of April.