Jessica Simpson is ''shocked'' her sister Ashlee has gone back into the world of reality TV.

The 38-year-old star - who has appeared on the likes of 'Newlyweds: Nick and Jessica' in the past - admitted she didn't expect her younger sibling to invite cameras into her home for 'Ashlee + Evan' alongside husband Evan Ross, after previously starring in 'The Ashlee Simpson Show'.

Speaking to 'Entertainment Tonight', Jessica said: ''She did a reality show [before], so I was shocked that she said yes to it, because it's like you're mic-ed for everything.

''[I asked her], 'Wait, are you sure you want everything to be out there?' And she's like, 'Yeah, I'm really confident'.

''That's what you have to have when you're doing reality, you know? You have to be confident in who you are and what you're standing for, and I think she is.''

The actress-and-singer's own show documented her first marriage to Nick Lachey and ran for three seasons between 2003 and 2005, but she insisted she has no plans to front another programme in that vein.

She explained: ''Oh, gosh no. I am confident, but I also know how people can take your words and make them whatever they want to make them.''

Both Jessica and Ashlee, 33, are set to return to the stage after spending some time on ''behind-the-scenes-type work'' after raising a family.

Although she will appear on her sister's show ''toward the end'', she said the focus is very much on Ashlee and Evan.

She added: ''[It's about their] journey together, and discovering music together, which is awesome.''

The couple share two-year-old son Jagger, while Ashlee is also mum to nine-year-old son Bronx, from her previous marriage to Fall Out Boy bassist Pete Wentz.

Meanwhile, Jessica and husband Eric Johnson have son Ace, five, and six-year-old daughter Maxwell.