Possible Clues:

• 'What's up ___ that?'
• Possessing hearts, card laid on top
• Using humour on husband
• Starring part in show, I think
• Go ___ the flow
• 'Paired up' follower
• In company of
• Part 3 of a Stephen Leacock quote
• See 1
• By means of, say, one of the calculations