More than 230 venues have signed up to take part in the seven-day celebration of independent music venues around the UK, which returns for its seventh consecutive year today (January 27) and runs until February 2.
"It's about spreading awareness and reminding people how important these venues are, said Calvi, who stressed the vital role the venues play in the overall music ecosystem.
"They are where artists develop their craft and that was definitely the case for me," she said. "I got to learn who I was as an artist through playing and meeting other artists at a similar level to me, so they are incredibly important. It's how I met artists that inspired my work and also how I learned to be a performer - because it takes practice."
The BRIT Award and Mercury Prize-nominated singer/songwriter namechecked London's The Garage, Notting Hill Arts Club, The Shacklewell Arms and The Old Blue Last among her favourites.
"I met one of my bandmates in the toilets of a tiny venue," she laughed. "She was playing drums in a band and I was playing bass in another band. We got talking and that's how I got my band together so that's an example of how you can meet people who then become really important parts of your life. That's a really good memory for me."
It will be great to go back to playing one of the venues that I cut my teeth on
Calvi's show at The Windmill in Brixton on January 31 is shaping up to be one of the standout moments of this year's IVW, which is funded in partnership with Arts Council England, Arts Council Wales, Creative Scotland, BBC 6 Music, BBC Sounds, Fred Perry, Harman, Musicians Union, PPL, PRS For Music, Yamaha and Yorkshire Tea.
Her performance forms part of the BBC 6 Homecoming Tour with Steve Lamacq, which will see the DJ take his BBC Radio 6 Music show to five UK cities – Newcastle, Sheffield, Cardiff, Exeter and London. Lamacq will also welcome Nadine Shah, Self Esteem, Gruff Rhys, Frank Turner, and Anna Calvi, from 4-7pm, January 27-31.
"I'm so excited," said Calvi. "BBC Radio 6 Music has been really supportive of my latest record, which obviously means a great deal to me and it will be great to go back to playing one of the venues that I cut my teeth on, it's quite emotional and I think it'll be a very exciting show."
Calvi called for Government support of the sector, arguing the grassroots scene was regularly overlooked in favour of other art forms.
"They are a vital part of the community of artists that exist in the UK," she said. "And actually, these artists often go on to bring in a lot money to the UK."
Other IVW tours and shows will include BC Camplight, Pigs x7, TOY, Sinead O’Brien, Demob Happy, Toyah Wilcox, Stereo MC’s Twin Atlantic, Morcheeba, Goat Girl, Black Country New Road and Raging Speedhorn.