LAS VEGAS — Fans knew they could expect club bangers, personal tracks and Britney Spears' signature sassiness with Britney Jean, but not many were expecting that her eighth album would feature a collaboration with sister Jamie Lynn Spears, who's making a musical comeback of her own.

The sisters teamed up on, "Chillin' With You," a mid-tempo song about sisterly love that has them singing, dancing, sipping wine and not having to worry about a thing.

MTV News recently caught up with Britney at Planet Hollywood Resort & Casino in Las Vegas, the home of her upcoming two-year Piece of Me residency, where she revealed that she knew that this was the right time to record a duet with her baby sister.

"You know, I just knew in my heart as I was doing the album, and I was like, I want my sister on this record," Spears said. "I knew I wanted her on the record and I was pushing for it."

And all the pushing paid off, even if it was hard to find time to lay down the track in between their busy personal lives.

"We worked it out with her schedule to come out because she has a baby, so it's hard for [her] to always come out and visit a lot," Britney said. "But she came out, we did it, we cut it, and I'm really excited about it."

Jamie Lynn recently released her country ballad, "How Could I Want More," the first song off her upcoming album. And fans, be on the lookout: there may be a chance that big sister Britney will return the favor and bring her own country flare to Jamie Lynn's debut.

"Yeah maybe," Britney said. "That would be cool."