U.S. President Joe Biden appeared to freeze on stage after speaking at a star-studded fundraiser in Los Angeles. Former President Barack Obama then stepped in to help him.

The incident, captured on video, adds to concerns about the 81-year-old president’s health. Biden’s physical and mental well-being have been questioned due to similar episodes.

In the video, Biden and Obama wave and smile at the cheering crowd in the Peacock Theater in downtown Los Angeles. Biden claps and gives a thumbs up before suddenly stopping and staring for several seconds.

Obama notices this, takes Biden by the wrist, and gently moves him along. Biden then seems to recover and continues as usual.