LOS ANGELES — Stephen Hawking may have an impeccable understanding of space-time, but his comedic timing is pretty good, too. At least, that’s according to recent co-star Simon Helberg on Twitter, who noted the theoretical physicist’s “understanding of comedy in relation to time” during his appearance on CBS’ “The Big Bang Theory” on Thursday.

In the episode, Howard (Helberg) subjects Sheldon (Jim Parsons) to a series of humiliating acts before he will hand Sheldon’s research thesis over to the scientist. Of course, Hawking wants to compliment Sheldon in person (and point out an error in his work), so the famous scientist appears in person.

It’s probably the first and only time you’ll ever hear a brilliant scientist say the word “boner” on network TV.

Even though Hawking suffers from the degenerative disease related to amyotrophic lateral sclerosis, which leaves him almost completely paralyzed and requires him to communicate through a computerized voice, he’s managed to be a visible media presence over the years.

He always plays himself, making guest appearances on “Star Trek: The Next Generation,” “Futurama,” “The Simpsons” and serving as host on the anthology series “Masters of Science Fiction.”

In past episodes, Leonard Nimoy, LeVar Burton, Stan Lee and Steve Wozniak all have made appearances on the hit CBS sitcom.

Heidi Klum files for divorce from singer Seal

LOS ANGELES — Heidi Klum moved to formally end her marriage Friday from singer Seal a little over two months after they separated, as the supermodel filed for divorce in a Los Angeles court.

The couple has four children together, including Klum’s daughter from a previous relationship. They had been married for more than six and a half years when they announced their separation in January, vowing to keep their breakup amicable.

Klum’s filing, which she signed Thursday, cites irreconcilable differences. The model and star of the TV competition series “Project Runway” is asking for sole physical custody of the children, with Seal getting visitation and joint legal custody.

The Grammy-winning soul and R&B singer, whose real name is Henry Samuel, released an album days after the couple announced their breakup and told talk show host Ellen DeGeneres that their split didn’t mean a total end to their relationship.

Current TV responds to Olbermann

LOS ANGELES — Current TV offered its rebuttal to a scathing lawsuit filed by Keith Olbermann by filing a countersuit Friday detailing alleged bad behavior by its former talk show host and seeking a judge’s ruling that he is not entitled to any more money from the network.

The network’s filing accuses Olbermann of breaching his contract by disclosing terms of the lucrative deal, refusing to cooperate in promoting the show and taking days off without permission.

The countersuit comes one day after Olbermann sued his former employer, claiming it violated his agreement, engaged in shoddy production values and owed him more than $50 million.

The network and Olbermann have been at odds for months, and the dispute has escalated in the days since the former “Countdown” host was fired last week.

Olbermann’s attorney Patricia Glaser said of Current’s countersuit: “No merit. No defense. And in our view, no problem.”

Current’s suit claims Olbermann has damaged the network and will continue to do so. It seeks unspecified damages.

The network’s filing paints Olbermann as a petulant figure after he was hired to be Current’s signature host, rejecting seven limousine companies, refusing to cooperate in promotional discussions and taking vacations with little notice.