The 'Teenage Dream' singer was threatened by the rapper after she criticised the message of his new song.
Jessie J Didn't Deserve MOBO Awards Says Lily Allen
The 'Smile' singer says that although she loves Jessie, there's no way she deserved to win four MOBO Awards.
Lily Allen made the comments after the 'Price Tag' singer triumphed at the 2011 MOBO Awards in Glasgow, picking up gongs for Best Album, Best Song, Best Video for 'Do It Like A Dude' and Best UK Act as voted for by Capital FM listeners.
But the former singer turned boutique owner objects to Jessie's wins on the grounds that her music doesn't fit the bill. "Now, I love Jessie J as much as the next person but how is her music "of black origin?" she wrote on Twitter.
"Is it cause she says "man dem" in her tune?" she continued.
Jessie J opened the show with a dance off with a lookalike at this year's MOBO Awards, where she was nominated for five awards and won four.
Latest Jessie J
The 'Impossible' star will perform at the huge gig in Dublin later this summer.
Ahead of her third appearance at the Summertime Ball in June, Capital checks out some pictures of Jessie J before she was famous.
The 'Who You Are' singer features on the soundtrack for the new Hollywood drama.