Comedy star Miranda Hart ended up across the net from her hero Tim Henman in a special film in aid of Sport Relief.
Viewers will see Miranda rubbing shoulders with sportsmen including Robbie Savage and Mo Farah during a visit to the Royal Albert Hall.
She will join other characters from self-titled sitcom Miranda - mum Penny (Patricia Hodge) and best friend Stevie (Sarah Hadland) - before ending up on court after being mistaken for a male tennis player.
Hart said: "I am a big Tiger Tim fan and was really quite star-struck - which is my excuse for the poor tennis. Otherwise I would have been smashing."
The film will be on the BBC as part of an evening of programmes for Sport Relief from 7pm.
The Call The Midwife star is one of dozens of big names taking part in Sport Relief, including John Bishop and Frank Skinner, who will try to raise money for charity by confronting his fear of water and swimming a width of a pool.