JUSTIN TIMBERLAKE has a unique way of avoiding getting hitched to longtime GF JESSICA BIEL – a marriage proposal!

The “Sexy Back” singer popped the question to the 29-year-old beauty during a Montana snowboarding vacation over the Christmas holiday, but pals say he only did it to buy more time as a bachelor!

“Justin knew that Jessica would dump him unless he committed to making her his bride, so his proposal was just lip service!” an insider told The ENQUIRER.

“He told friends that he has no intention of rushing down the aisle and he only went through with the engagement to get Jessica off his back.

“Justin says that it’ll be at least a year and probably several more before they actually tie the knot.”

The on-off couple began dating in 2006 but broke up in March 2011, only to reunite over the summer.

“Justin loves Jessica, but he also cherishes his freedom,” continued the source. “He wants to be in a relationship with Jessica, but not necessarily as a married couple.

“But marriage and kids is the end goal for Jessica, and she told Justin late last year that she’d break up with him for good unless he agreed to settle down with her.

“Rather than keep dealing with Jessica’s nagging, Justin caved to the marriage pressure.”

Justin, 30, reportedly presented Jessica with a custom-designed engagement ring, and she’s already making plans for the big day.

“But Justin fully intends to ride the engagement phase,” the source added.

“He wants to remain a single guy as long as possible.”