Q: I know that “Law & Order: Special Victims Unit” is marking its 20th anniversary on the air. Has Mariska Hargitay been on the show the entire time?

— Kevin Prescott, Bend

A: Pretty much. The only time she was absent from the NBC series and the role of Olivia Benson for a significant stretch was when she was pregnant in 2006, and during her maternity leave, Connie Nielsen was brought in as a temporary partner for Elliot Stabler (Christopher Meloni). Nielsen reunited very briefly with Executive Producer Dick Wolf for this season’s CBS “FBI,” but she left that show after the pilot episode.

Hargitay has worn additional hats as “L&O: SVU” has continued, becoming an executive producer of the show as of Season 18, and also directing several episodes — five as of this writing. She also used some of the information she discovered through the series to produce and host the HBO documentary special “I Am Evidence,” about rape kits (or sexual assault forensic exams) left unexamined by authorities, earlier this year.

Q: Did Beth Behrs do any other series work between “2 Broke Girls” and her new show “The Neighborhood”?

— Annie Grant, via email

A: She stayed loyal to CBS — be that by choice, or simply because that’s where her opportunities were — by making a guest appearance in an episode of “The Big Bang Theory,” and she also took part in last December’s 50th-anniversary salute to “The Carol Burnett Show.”

Interestingly, when she did the latter special, it wasn’t known that Behrs would be returning to CBS full time. The pilot for “The Neighborhood” was filmed with another actress in her eventual role, and a bid for Broadway hadn’t worked out for her, so she was available when the call came (facilitated in part by co-star Max Greenfield, a friend of hers) for her to move into “The Neighborhood.”

Q: Will “Marvel’s Agent Carter” ever return?

— Melissa Burns, Leesburg, Florida

A: Apparently not, though there had been some talk of a Captain America-based podcast into which the Peggy Carter character would have factored. As it stands, 18 episodes were produced over two seasons (2015-16) for ABC, which had ordered the Hayley Atwell-starring series without requiring a pilot to be made first. Had there been a third season, the show’s setting might have been relocated from Los Angeles to London, per executive producer Michele Fazekas … and Atwell added that more of Carter’s family history would have been explored.

Q: Didn’t Yaya DaCosta of “Chicago Med” play Whitney Houston in a movie?

— Linda Brand, Buffalo, New York

A: She did. Arguably best-known before that as the runner-up in the third season of “America’s Next Top Model,” DaCosta had a relatively brief run in “All My Children” and also appeared on such shows as “Ugly Betty,” “Law & Order: Special Victims Unit” and “House” before landing what can be deemed her truly big break in the title role of Lifetime’s 2015 biography of superstar Houston. Angela Bassett — who had acted with Houston in “Waiting to Exhale” (and whose husband, Courtney B. Vance, starred in “The Preacher’s Wife” with Houston) — made her directorial debut with the film.

Q: Someone told me that Ryan Eggold, who’s now on “New Amsterdam,” used to be on “Beverly Hills, 90210.” Is that true?

— Cindy Lewis, via email

A: It actually was the revival of the series, titled just “90210,” which had a five-season run (2008-13) on The CW. During its first three years, Eggold played Ryan Matthews, a teacher at West Beverly High who was a maverick among faculty members — making him quite popular with his students, but not so much with his peers on the staff. In fact, Matthews became romantically involved with a supposed pupil, but she turned out to be a police officer who was working an undercover detail at the school.

Matthews also had a romantic link to Kelly Taylor (Jennie Garth, who reprised her original role on a recurring basis), but he engaged in a brief liaison with Brenda Walsh (Shannen Doherty, who also revived her character from the earlier show). Eggold left “90210” to focus on making feature films, but NBC’s “The Blacklist” brought him back to series television.

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