The singer and actor Justin Timberlake apologized to Britney Spears and Janet Jackson on Friday in a vague but earnest Instagram post, a week after a New York Times documentary on Spears set off a wave of criticism of Timberlake for how he treated the pop star after their breakup.

The apology to Jackson seemed to stem from the infamous Super Bowl halftime performance in 2004, when a closing duet between Timberlake and Jackson ended with Timberlake singing “Bet I’ll have you naked by the end of this song” as he tore away more of her costume than had been planned, to reveal — live and televised worldwide — her uncovered breast. In the aftermath, Jackson was the subject of most of the backlash, and Timberlake later conceded that he should have defended her more.

Without specifying what exactly he was apologizing for, Timberlake wrote that he had seen all the messages, tags and comments on social media in recent days and that he was “deeply sorry for the times in my life where my actions contributed to the problem, where I spoke out of turn, or did not speak up for what was right.”

“I understand that I fell short in these moments and in many others and benefited from a system that condones misogyny and racism,” he said in the post.

The documentary, “Framing Britney Spears,” which premiered on Hulu and FX on Feb. 5, included a re-examination of the world’s reaction to Timberlake and Spears’s breakup, which was framed in the media as being Spears’s fault — partly because a music video by Timberlake implied that Spears had cheated on him. It included a clip from a radio interview with Timberlake in which he was asked whether he had sex with Spears and he replied, “OK, yeah, I did it,” evoking cheers.

The documentary prompted calls on social media for direct apologies from many people who made jokes at Spears’s expense or interviewed her in ways now viewed as insensitive, sexist or simply unfair. But one of the most prominent apologies sought by fans was from Timberlake; others piped up to ask, “What about Janet Jackson?”

The mea culpa eventually landed.

“I specifically want to apologize to Britney Spears and Janet Jackson both individually, because I care for and respect these women and I know I failed,” the post from Timberlake said. “Because of my ignorance, I didn’t recognize it for all that it was while it was happening in my own life but I do not want to ever benefit from others being pulled down again.”

In the aftermath of the Super Bowl halftime show, Timberlake apologized to the program’s audience as well as “anyone offended.” At the Grammy Awards, which that year followed the Super Bowl, he won two awards, while apologizing for the “unintentional” incident. Years later, he said in an interview with MTV, “There could have been ways that I could have gone about it, handled it better.”