Justin Timberlake's grandmother has revealed that the recent reports suggesting he is engaged to on-off girlfriend and Hollywood actress Jessica Biel are true. 

Just before Christmas, on December 21, news broke that the 'SexyBack' star had popped the question to Biel while they were on vacation in Wyoming although they still haven't publicly confirmed the engagement.

Timberlake's grandmother, Sadie Bomar, has now explained to GossipCop.com that the pair are set to be married and she opened up about the moment he told her the happy news: "He called me on Christmas Day and told me he’s engaged."

Bomar also added that the couple asked family members to wait "until after the holidays" to reveal details on the celebration so they could enjoy the moment in privacy and admitted that "the family loves Jessie… she’s a very sweet girl".