Selena is proposing to Justin because "she hates seeing him so upset over the paternity allegations"

JUSTIN BIEBER is going to find a big surprise “Under the Mistletoe” – an engagement ring from his girlfriend SELENA GOMEZ!

The 19-year-old Disney star knows a proposal will show Justin, who was recently hit with an ugly paternity lawsuit, that she’ll always stand by him, sources say.

“Selena is crazy about Justin, and she hates seeing him so upset over the paternity allegations,” a friend revealed.

“He’s been on edge thinking Selena might leave him, so she wants to get him a ring to show that she’s with him for the long haul.”

The 17-year-old “Baby” singer’s world turned upside down in October when Mariah Yeater, 20, of San Diego, Calif., filed a hand-signed affidavit claim­ing he fathered her now 4-month-old son when the two had a sexual romp after a sold-out show at Los Angeles’ Staples Center last year. Bieber denies the woman’s claims.

Since then, Justin has been talking about starting a family with Selena, but as The ENQUIRER has reported, family and friends are begging them to slow down their relationship.

The two have dated for 11months, and Selena plans to give Justin the ring in front of his family in Canada over the holidays, said the source.

“Even Justin’s mom Pattie is in on the secret,” the source added.

“Pattie thinks Justin is talking about having kids partly because he’s afraid of losing Selena. But if Selena proposes, Pattie thinks Justin will feel more secure, and she’ll be able to talk them into putting off a wedding and kids.”