The two singers took to the stage together on Monday (August 20) to perform their collaboration 'True Love' for a VH1 Storytellers show which will be broadcast in November.
Allen - who recently confirmed that she will release all future material under her married name Lily Rose Cooper - told The Sun: "It was great, [it] felt strange being back on stage again but Pink made me feel at ease.
"I really enjoyed myself though [and] can't wait to get back out there."
'True Love' will feature on Pink's sixth studio album The Truth About Love, which will be released on September 17 in the UK and on September 18 in the US.
Pink will also appear at the iTunes Festival on Thursday, September 13.
Watch the video for 'Blow Me (One Last Kiss)' by Pink below: