Joe got a big surprise when Blue Peter's Helen and Barney invaded Newsround HQ... dressed in their PJs!
No - they hadn't mistaken it for the BP studio, but they wanted to tell people about Go Pyjamas! and even brought along a onesie so Joe could join in too.
Through the Go Pyjamas! appeal Blue Peter are turning the UK into a giant pyjama party for Children in Need and want you to get sponsored to wear your PJs somewhere unexpected.
This could be at school, work, Scouts, football, a party, on a rollercoaster… anywhere!
And there'll a big grand finale appeal show on Thursday 15 November, the night before Children in Need.