The stepson of a British billionaire aboard a missing Titanic-bound sub went online to flirt with a nearly nude Only Fans model Wednesday as rescuers raced to find the vessel.

Brian Szasz,  the stepson of wealthy British explorer Hamish Harding, retweeted an image of Only Fans it-girl Brea flashing her booty in a thong with the caption, “can i sit on u” on Twitter Wednesday as the high-stakes rescue mission unfolded.

“Yes please!” Szasz gushed enthusiastically.

The post came just minutes after he asked followers to “please keep my family in your prayers.”

Szasz — who boasted Monday that he attended a Blink 182 concert amid the search for his stepdad —   came under fire by some observers, who called his latest post tone-deaf.

“Lmao quote tweeting a thirst trap while your stepdad is lost at sea is wild business ????” one commenter wrote — as another slammed, “Unreal to be tweeting this [right now.]

Another user added,  “This guy loves blink- 182 and having ladies sit on his face and he’s not afraid to let the world know.”

Harding, 58, is one of the five people who could be trapped 12,000 feet underwater on the OceanGate submersible that vanished while headed to the Titanic wreckage site over the weekend.

Search crews were desperately scrambling to find the passengers  — as US Air Force planes and  critical equipment were delivered late Tuesday —  in a “last chance” effort to save them, authorities said.

If Harding and the others are still alive,  they would have less than 40 hours of oxygen left, according to the US Coast Guard.

On Monday, Szasz announced he was going to attend the punk rock concert in San Diego, California then later posted a photo of himself grinning and sporting a Blink-182 at the show.

His billionaire stepdad once traveled to space aboard one of Jeff Bezos’ Blue Origin missions, and has set a world record for the fastest circumnavigation of the Earth to visit both poles.