Singer and actress Jessica Simpson is set to star in a scripted comedy at NBC, which will be based on her life. Simpson also stars in the network’s reality competition “Fashion Star,” which returns on March 8. Nick Bakay will write the script for the pilot.

NBC has promoted Doug Vaughan to executive vice president of special programs and late night programming, reporting to the network’s president of alternative and late night programming Paul Telegdy. Vaughan had been senior vice president and recently oversaw the “Hurricane Sandy: Coming Together” telethon.

Actress Maggie Smith has signed on for the fourth season of PBS’s “Downton Abbey,” according to TVLine.com. Smith’s return was in question after creator Julian Fellowes said last summer he didn’t know if she’d be back.

Arnold Worldwide has brought in Tristan Kincaid as a creative director, working in the agency’s New York office. Kincaid was previously a creative director at Ogilvy & Mather.

IPG Mediabrands’ media barter unit Orion Trading has promoted Scott Downs, naming him executive vice president and director of client and media services. Downs was previously senior vice president and replaced Laura Ryan, who was promoted to president.

Guggenheim Digital Media, the newly named company that owns Billboard, The Hollywood Reporter and AdWeek, has named Ross Levinsohn chief executive officer. Levinsohn was most recently interim chief executive officer at Yahoo.

Tas Viglatzis has been promoted to chief financial officer at The FT Group, which runs the newspaper The Financial Times. Viglatzis had been director of strategy.

Jonathon Shaevitz has been named chief executive officer at Legolas Media, which runs an online media buying platform. Shaevitz had been chief executive at Maxifier.

Rebecca Schmitt has been named vice president at TotallyHer.com, which operates a number of sites for women, teens and families. Schmitt was previously vice president of product development at LoveIt.

Showtime has brought in Sharyn Alfonsi as a contributor to “60 Minutes Sports,” its new sports-focused newsmagazine. Alfonsi was most recently a correspondent at ABC News.

NBC Sports group has named Eric Grilly president of its business Alli Sports, which runs action sports events such as the Dew Tour and Red Bull Signature Series. Grilly was previously executive vice president and chief digital officer for NBC Regional Networks.

Tags: Eric Grilly, Jessica Simpson, Jonathon Shaevitz, Laura Ryan, Rebecca Schmitt, ross levinsohn, Sharyn Alfonsi, Tas Viglatzis