The Motown legend will serenade guests as her 25-year-old son ties the knot with Ashlee Simpson on the evening of August 31 in a romantic ceremony held at her own mansion in Greenwich, Connecticut.
The 70-year-old diva is going to be joined on stage by her daughter Rhonda Ross Kendrick, E! Online is reporting.
And Diana has pulled out all the stops to make the wedding an A-list affair, adding none other than Stevie Wonder and Smokey Robinson to the guest list and fuelling rumours of a one of a kind performance.
'The Hunger Games: Mockingjay' actor Evan previously admitted The Supremes singer was taking a very hands-on role in planning his wedding.
He said: ''[My mother is] involved in every part of our wedding [and] engagement party.''
Evan also revealed he was so desperate to be married to Ashlee - who has a five-year-old son, Bronx, from her marriage to Fall Out Boy star Pete Wentz - that he was considering eloping.
He said: ''Honestly, we could go and get married right now, wherever. We just want to be married. We're in love.''
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