It's not just Apple (Nasdaq: AAPL) cornering the market on The Beatles these days. Sirius XM Radio (Nasdaq: SIRI) is calling in one of The Fab Four in to celebrate a milestone of its own.

The satellite radio giant will be hosting a concert by Paul McCartney at Harlem's legendary Apollo to celebrate hitting the impressive mark of 20 million subscribers.

Sirius XM is going all out for this, complete with a contest to give away 125 pairs of tickets to active subscribers, as well as a grand prize that will include round-trip airfare, lodging, and special access.

Either way, all Sirius and XM subscribers will be able to listen to the concert as it's broadcast live on both satellite networks. There will also be a monthlong channel set up to help McCartney promote the CD reissue of his landmark Band on the Run solo album.

It's not a surprise that Sirius XM will pass 20 million subscribers next month. It closed out the third quarter with nearly 19.9 million accounts, raising its guidance to close out the year with 20.1 million subs. It is now the country's second largest premium entertainment subscription service, trailing only Comcast (Nasdaq: CMCSA) -- and the cable provider has been shedding video customers lately. Sirius XM should overtake Comcast in a year or two, if Netflix (Nasdaq: NFLX) doesn't grab the crown first.

McCartney may be an interesting name to headline the milestone, but he's more cutting-edge than his former band's late arrival at the iTunes Music Store suggests. Three years ago, McCartney eschewed the major labels by releasing a new studio album through Starbucks (Nasdaq: SBUX). Why not go for a private celebratory event, especially if it's accompanied by a temporary channel that will drum up sales for his existing catalog of music?

It makes sense -- just like a silly love song.

What's your take on Sirius XM's celebratory shindig? Share your thoughts in the comment box below.