No rest for the weary!

Less than 24 hours after staging her fall 2014 fashion show in New York, Victoria Beckham hit up Barry's Bootcamp for a morning sweat session.

The on-the-go mama of four was "very unassuming" when she arrived bright and early for the 8:20 class Monday in Chelsea, an onlooker told us.

"She expected no special treatment at all and waited outside the studio doors just like everyone else," said the spy, adding that she was "very friendly" to other classgoers.

While the slim-figured designer flew solo for her workout Monday, Sunday's fashion show was a family affair, with hubby David Beckham and kids Brooklyn, Romeo, Cruz and Harper all sitting in the front row.