How Bristol, Levi Johnston kept their relationship a secret from Sarah Palin

Washington, July 15 (ANI): After the announcement of Sarah Palin's daughter Bristol and Levi Johnston's engagement, it has emerged that the couple went to great lengths to keep their relationship a secret from the former vice presidential candidate.

The two have been living together in Anchorage, Alaska, for some time, neighbours have revealed.

"Even though Levi spends the night at Bristol's every single night, they have to be on high alert in case Sarah stops by to see Tripp," Radaronline.com quoted one neighbour as saying.

"As soon as they hear her car, Levi escapes out the back door and waits for a text from Bristol to tell him the coast is clear," the neighbour added.

Bristol and Levi have announced that they were engaged, again, after twelve months of custody fights, child support battles. (ANI)